71-00-00 Oct 95 - FlyingWay · cfm international CFM56-3 TRAINING MANUAL EFFECTIVITY CFMI PROPRIETARY INFORMATION Page 2 ALL 71-00-00 Oct 95 GROUND SAFETY PRECAUTIONS Overview (1.A.a)

cfm international CFM56-3 TRAINING MANUAL

EFFECTIVITY

CFMI PROPRIETARY INFORMATION

Page 1Oct 95ALL 71-00-00

GENERAL ENGINE DATAObjectives:At the completion of this section a student should be able to:....given a list identify the safety precautions associated with the CFM56-3/3B/3C engine (1.A.x).....given a specific model and a list identify the dimensions and weights of the CFM56-3/3B/3C engine (1.A.x).....given a specific model and a list identify the ratings and applications of the CFM56-3/3B/3C engine (1.A.x).....given a list recall the engine transportation requirements for a CFM56-3/3B/3C engine (1.A.x).....given a list recall the types of on-condition monitoring used with the CFM56-3/3B/3C engine (1.A.x).....given a list recall the maintenance strategy of the CFM56-3/3B/3C engine (1.A.x).....given a list select the purpose of on-condition monitoring for the CFM56-3/3B/3C engine (1.B.x).....given a list select the purpose of the maintenance strategy of the CFM56-3/3B/3C engine (1.B.x).


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GROUND SAFETY PRECAUTIONS

Overview (1.A.a)The operation of jet power plants is dangerous. Whilethe engine operates, these dangerous conditions canoccur:

- There is a very strong suction at the front of theengine that can pull persons and unwantedmaterials into the air inlet.

- Very hot, high speed gases go rearward from theturbine exhaust nozzle.

- The fan exhaust at high thrust has very high speed.

- When the Thrust Reverser (T/R) is extended, thefan exhaust goes forward while the turbine exhaustgoes rearward.

- When exposed to engine noise for extended periodsof time hearing loss can occur.

- High voltage output from the ignition system can befatal if not properly handled.


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THE HAZARDS OF AIRCRAFT MAINTENANCE


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When an engine is started, fuel that has collected in theturbine exhaust sleeve can ignite. Long flames are blownout of the exhaust nozzle. For this reason all flammablematerials must be kept clear of the exhaust nozzle.

There are contamination and bad gases which werepulled into the engine by suction. There are also gasesfrom the fuel that has burned or fuel which has notburned. These gases in the exhaust are dangerous toyou. Tests have shown that the amount of carbonmonoxide in the exhaust is small, but there are othergases in the exhaust that smell bad and can cause injuryor irritation to your eyes and lungs. These gases willusually cause a watering or burning sensation to youreyes. Less noticeable, but more important, is therespiratory irritation. When working near running aircraftyou must stay away from small spaces where thesegases can collect.


Inlet and Exhaust Safety Precautions (1.A.a)Persons positioned near the power plant during powerplant operation must be aware of the following inlet/exhaust hazard areas:

When the engine operates, it makes a low air pressurearea in the inlet. This low pressure area causes a largequantity of air to move from the forward side of the inletcowl and go into the engine The air which is near theinlet moves at a much higher velocity than air which isfarther from the inlet. The quantity of the engine suctiondoes not increase slowly and continuously when you gonear the inlet. The suction is small until you get near theinlet, where the suction increases suddenly. The enginesuction can pull small objects into the engine easier thanit can pull large objects.

Aft of the inlet cowl lip the hazard area extendscompletely around the outer diameter and to the forwardend of the power plant.

When the engine operates, a large quantity of exhaustcomes from the aft end of the engine. The exhaust is hotand moves at high speed. The exhaust temperaturenear the engine is sufficient to melt bituminous (asphalt)pavement engine operation on concrete pavement istherefore recommended.


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THIS PAGE INTENTIONALLY LEFT BLANK


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Inlet and Exhaust Safety PrecautionsBefore you operate the engine, do these steps:

- Make sure there are no tools, unwanted materialsor objects in the air inlet.

- Make sure the area 40 feet to each side andforward of the power plant is clean.

- Make sure the ground which is forward of theengine is strong and solid.

- Make sure the suction of the engine will not pull theunwanted material on the ground into the engine.

- Make sure that persons with loose objects (such ashats, eyeglasses, loose clothing or rags) do not gointo this area.

- When the engine is operated, use an engine inletguard. This will prevent persons from being pulledinto the inlet because of air suction from the engine.

It is recommended that ground persons stay outside ofthe inlet hazard area for at least 30 seconds after the fuelcutoff signal (start lever placed in CUTOFF position)from the flight compartment.


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PROTECT AGAINST INLET HAZARDS


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Inlet and Exhaust Safety PrecautionsAt idle power (forward thrust), the inlet hazard area startsfour feet aft of the inlet cowl lip and extends to a distanceof approximately 9 feet forward. The exhaust hazardarea extends aft to a distance of approximately 100 feetfrom the tail of the B737 aircraft.

- If the surface wind is more than 25 knots, increasethe distance of the inlet hazard area by 20%.

- If the ramp surfaces are wet or frozen, make theramp clean to prevent injury to persons.

- After the engine is shut down, let the engine spooldown before the engine is approached.


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100 FEET(30.5 METERS)

WARNING: IF SURFACE WIND IS REPORTED GREATERTHAN 25 KNOTS, INCREASE DISTANCE OFINLET BOUNDARY BY 20%. IF RAMP SURFACESARE SLIPPERY, ADDITIONAL PRECAUTIONSSUCH AS CLEANING THE RAMP WILL BENECESSARY TO PROVIDE PERSONNELSAFETY.

GROUND PERSONNEL MUST STAND CLEAR OFTHESE HAZARD ZONES AND MAINTAINCOMMUNICATION WITH FLIGHT COMPARTMENTPERSONNEL DURING ENGINE RUNNING.

ENGINE INLET AND EXHAUST HAZARD AREAS - IDLE POWER (FORWARD THRUST)

R = 9 FEET(2.7 METERS)

INLETCOWL

LIP

RIGHT ENGINE

4 FEET(1.2 METERS)

LEFT ENGINE


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Inlet and Exhaust Safety PrecautionsAt breakaway power (forward thrust), the inlet hazardarea starts five feet aft of the inlet cowl lip and extends toa distance of approximately 13 feet forward. Theexhaust hazard area extends aft to a distance ofapproximately 510 feet from the tail of the B737 aircraft.




At high power, the fan and turbine exhaust can blowloose dirt, stones, sand and other unwanted materials ata distance of 300 feet. Park at an area where injury topersons or damage to equipment or other airplanes canbe prevented. When available use a blast fence todeflect the thrust if the engines are operated withoutsufficient space to decrease the fan and turbine exhaustthrust to zero.


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ENGINE INLET AND EXHAUST HAZARD AREAS - BREAKAWAY POWER (FORWARD THRUST)

R = 13 FEET(4 METERS)

5 FEET(1.5 METERS)

INLETCOWL

LIP



510 FEET(155 METERS)


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Inlet and Exhaust Safety PrecautionsAt takeoff power (forward thrust), the inlet hazard areastarts five feet aft of the inlet cowl lip and extends to adistance of approximately 13 feet forward. The exhausthazard area extends aft to a distance of approximately1900 feet from the tail of the B737 aircraft.






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ENGINE INLET AND EXHAUST HAZARD AREAS - TAKEOFF (T/O) POWER

1900 FEET(579 METERS)

R = 13 FEET(4 METERS)

5 FEET(1.5 METERS)

INLETCOWL

LIP


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Inlet and Exhaust Safety PrecautionsAt idle power (reverse thrust), the inlet hazard area startsfour feet aft of the inlet cowl lip and extends to a distanceof approximately 9 feet forward. The secondary exhausthazard area extends to a distance of approximately 40feet forward of the exhaust nozzle while the primaryexhaust hazard area extends aft to the tail of the B737aircraft.





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WARNING: GROUND PERSONNEL MUST STAND CLEAR OFTHESE HAZARD ZONES AND MAINTAINCOMMUNICATION WITH FLIGHT COMPARTMENTPERSONNEL DURING ENGINE RUNNING.

45°

45°



ENGINE INLET AND EXHAUST HAZARD AREAS - IDLE POWER (REVERSE THRUST)


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Inlet and Exhaust Safety PrecautionsAt breakaway power (reverse thrust), the inlet hazardarea starts five feet aft of the inlet cowl lip and extends toa distance of approximately 13 feet forward. Thesecondary exhaust hazard area extends to a distance ofapproximately 130 feet forward of the exhaust nozzlewhile the primary exhaust hazard extends aft 175 feetfrom the tail of the B737 aircraft.






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45°

45°

175 FEET(53.3 METERS)

ENGINE INLET AND EXHAUST HAZARD AREAS - BREAKAWAY POWER (REVERSE THRUST)

WARNING: GROUND PERSONNEL MUST STANDCLEAR OF THESE HAZARD ZONES ANDMAINTAIN COMMUNICATION WITHFLIGHT COMPARTMENT PERSONNELDURING ENGINE RUNNING.


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Entry Corridor Safety Precautions (1.A.a)During the engine runs for maintenance which positionyou near the engine (such as during an idle leak check),enter and exit the engine fan case area in the entry/exitcorridor.


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WARNING: ENTRY/EXIT CORRIDOR MUST BE USED ONLY UNDERFOLLOWING CONDITIONS:

1. ENGINE OPERATION MUST NOT EXCEED LOW IDLEREVOLUTIONS PER MINUTE (RPM) WHILEPERSONNEL ARE IN ENTRY/EXIT CORRIDOR.

2. POSITIVE COMMUNICATION BETWEEN PERSONNELIN FLIGHT COMPARTMENT AND PERSONNEL USINGENTRY/EXIT CORRIDOR IS MANDATORY.

3. INLET AND EXHAUST HAZARD AREAS MUST BESTRICTLY OBSERVED BY PERSONNEL IN ENTRY/EXIT CORRIDOR.

4. USE OF SAFETY LANYARD IS RECOMMENDED (SEESHEET 2 AND 3).

IF SURFACE WIND IS REPORTED GREATER THAN25 KNOTS, INCREASE DISTANCE OF INLET BOUNDARYBY 20%. IF RAMP SURFACES ARE SLIPPERY,ADDITIONAL PRECAUTIONS SUCH AS CLEANING THERAMP WILL BE NECESSARY TO PROVIDE PERSONNELSAFETY.

ENTRY/EXITCORRIDOR

ENTRY/EXITCORRIDOR

5 FEET

45°

ENTRY/EXIT CORRIDOR (LOW IDLE)

A

ASEESEE

9 FEET

A

ENTRY/EXIT CORRIDOR

EXHAUSTHAZARD

AREA

EXHAUSTHAZARD

AREA

4 FEET

INLETHAZARD

AREA


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Entry Corridor Safety PrecautionsThe safety lanyard, inlet barrier or the inlet guard arerecommended for your safety.


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1. TO APPROACH OUTBOARD SIDEOF ENGINE, ENTER FAN CASEAREA FROM AFT END OF FANCOWL PANEL.

2. TO APPROACH INBOARD SIDE OF ENGINE, START WELLFORWARD OF INLET HAZARD ZONE. WALK AFT WITHSHOULDER NEXT TO FUSELAGE, CROSS OVER TOWARDENGINE AT A POINT JUST FORWARD OF LANDING GEAR,AND ENTER FAN CASE AREA FROM AFT END OF FAN COWLPANEL.

NOTE: USE OF SAFETY LANYARD IS RECOMMENDED

HOW TO APPROACH/EXIT FAN CASE AREA DURING ENGINE MAINTENANCE RUN

NOTE: PRIOR TO ENGINE OPERATION, THE PLUG-INPERSONNEL INLET BARRIER OR ENGINERUN-UP INLET GUARD MAY BE POSITIONEDAT THE ENGINE INLET AS AN ADDEDPRECAUTION

FUSELAGE

TO INBOARD SIDE OFNO. 2 ENGINE AND AIR

CART DISCONNECT

TO OUTBOARD SIDEOF NO. 2 ENGINE

SEE

AIRPLANEC

TO INBOARD SIDEOF NO. 1 ENGINE

TO OUTBOARD SIDEOF NO. 1 ENGINE

INLETHAZARD

AREA

INLETHAZARD

AREA

SAFETYLANYARD

F

INLETHAZARD

AREA

B

L

BC

SEE

SEE


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Cooldown Safety Precautions (1.A.a)After engine operation, make sure the turbine exhaustsleeve and plug have become sufficiently cool beforemaintenance is done in these areas.

The other parts of the engine can be worked on with nodanger of burns.


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GENERAL ENGINE DATA

Noise Safety Precautions (1.A.a)The engines make sufficient noise to cause damage toyour ears.

- You can temporarily cause your ears to becomeless sensitive to sound, if you listen to loud enginenoise

- You can become permanently deaf if you listen tothe engine noise for a long time

- Noise can affect the ear mechanism and causeunsteadiness or an inability to walk or stand withoutreeling

When you are near an operating engine, always use earprotection to decrease the quantity of sound energywhich reaches your ears.

Note: The use of both cup-type ear protection and earplugs is recommended.

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60 FEET (20 M)

30 FEET (10 M)

150 FEET (50 M)

T/O POWER

WARNING: EAR PROTECTION REQUIRED WITHIN THIS AREA.WARNING: PROLONGED EXPOSURE WITHIN THIS AREA OF

MORE THAN SIX MINUTES, EVEN WITH EARPROTECTION, CAN CAUSE EAR DAMAGE

ENGINE NOISE HAZARD AREAS

IDLE POWER

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Page 26Oct 95ALL


Ignition Safety Precautions (1.A.a)The engine ignition system is an electrical system withhigh energy. You must be careful to prevent electricalshock. Injury or death can occur to you. Do not domaintenance on the ignition system when you operatethe engine.

Open the circuit breakers for the ignition system todeactivate the ignition system. Manually ground theexciter terminal to discharge the current.

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Page 27Oct 95ALL

1 2

A

B

SEE

SEE

BOTHENGINE START

GRDOFF

CONTFLT IGN

LIGNR

FLTCONT

OFFGRD

21

PILOTS' CENTER INSTRUMENT PANEL

START VALVEOPEN

START VALVEOPEN

ENGINE START AND IGNITION MODULE LOCATION

PILOTS' OVERHEAD PANEL

A

B

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Page 28Oct 95ALL

DIMENSIONS AND WEIGHTS

Dimensional Data (1.A.a)inch mm

*Engine Overall Length 98.16 2,722Fan Inlet Case Forward Flange Diameter 63.39 1,610Fan Frame Rear Outer Flange Diameter 40.63 1,032Fan Major Module Length 33.81 859Core Engine Major Module Length 51.60 1,310TRF Outer Flange Diameter 40.63 1,032LPT Major Module Length 76.17 1,935

*Indicates from tip of spinner cone to rear end of cageassembly.

Weight Data (1.A.a)Basic Engine Weight lb kg

Dry 4,240 1,923Serviced 4,297 1,949Drained 4,252 1,929

With QEC Installed on Engine 5,340 2,420Fan Major Module 1,536 697Core Engine Major Module 1,400 635LPT Major Module 812 369

Note: All of the above engine values are approximateand may vary slightly.

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93.06 (2,634)33.81 (859)

40.63(1,032)

105.74 (2,686)

A

33.583 (980)

66.386(1,610)

43.898(1,115)

34.646(880)

VIEW A

CFM56-3 ENGINE OVERALL DIMENSIONS

Note: Dimensions are ininches with millimeters inparentheses

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RATINGS AND APPLICATIONS

Thrust Ratings (1.A.a)The CFM56-3 is available in these various power plantthrust ratings:

CFM56-3-B1 - 18,500 and 20,100 lbs.

CFM56-3-B2 - 20,100, 22,000 and 22,100 lbs

CFM56-3C - 18,500, 20,100, 22,100 and 23,500 lbs.

Aircraft Applications (1.A.a)The CFM56-3 was designed specifically for the BoeingSeries 737 airframe. The CFM56-3 is available in theseCommercial Boeing Series 737 airframe configurations.

CFM56-3-B1 - B737-300 and 737-500.

CFM56-3-B2 - B737-300 and 737-400.

CFM56-3C - B737-300, 737-400 and 737-500.


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CFM56-3 THRUST AND AIRFRAME CONFIGURATION CHART

737-300 737-400

BASIC ENGINE èCFM56-3C-1* @

20,000 LB THRUSTCFM56-3C-1* @

22,000 LB THRUST

CFM56-3C-1* @ 22,000 LB THRUST

CFM56-3C-1* @ 23,500 LB THRUST

OPTIONAL ENGINES èCFM56-3C-1* @

20,000 LB THRUSTCFM56-3B-2 @

22,000 LB THRUST

CFM56-3B-2 @ 22,000 LB THRUST

* May use higher thrust at SL/temperature > 86 degress F or high altitude airpor t


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RATINGS AND APPLICATIONS

Data Plate (1.A.a)To locate the specific engine model and thrust rating youmust first locate the engine data plate.The engine dataplate is located at 3:30 o'clock/ALF on the fan inlet casebetween flanges "B" and "C".

The engine plate provides the following information:- Engine Model Number

- Engine Serial Number

- Thrust Ratings

- Production Number

- FAA/DGAC Type Certificate

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ENGINE DATA PLATE

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A C J KB N T


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TRANSPORTATION REQUIREMENTS

Requirements (1.A.a)The compact physical dimensions of the CFM56-3 makefor convenient shipment of the engine withoutdisassembly.

Shipping a CFM56-3 engine by trailer over the roadrequires certain precautions that must be taken to ensurethat the engine is properly protected from internaldamage while in transit. The trailer must be equippedwith an air-ride suspension system for one enginetransportation. When shipping two or more engines,both the tractor and trailer must be equipped with an air-ride suspension system.

The CFM56-3 engine assembly can be shipped in somenarrow or wide body aircraft (Engine Axis Must BeParallel To Aircraft Axis). When transporting in low cargocompartments it will be necessary to separate the engine

When the CFM56-3 engine is reassembled on-site, it is"NOT NECESSARY" for a test cell run before reinstallingengine on the aircraft.


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SHIPPING CONTAINERS

FAN G/B ASSEMBLY108 X 92.5 X 71 INCHES

CORE ENGINEASSEMBLY

65 X 47 X 58 INCHES

LPT ASSEMBLY106 X 73.5 X 48 INCHES

LOW PRESSURETURBINE

CORE ENGINE

FAN WITHACCESSORY DRIVE

CFM56 TRANSPORTABILITY

ASSEMBLED ENGINEMINIMUM CARGO DOOR

L = 127.5 INCH (3,239 MM)H = 78.0 INCH (1,982 MM)


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ON-CONDITION MONITORING

Description (1.A.a)The engine design includes all the features necessary forin-flight and ground fault detection and isolation.

The condition monitoring program incorporates themaximum utilization of existing, proven techniques andthe development of new and improved diagnosticmethods.

The CFM56-3 on-condition monitoring system consistsof:

- Gas path health monitoring

- Borescope inspection capability

- Gamma Ray inspection capability

- SOAP (Spectral Oil Analysis Program)

- Lube particle analysis

- Vibration monitoring system

Purpose (1.B.a)The on-condition maintenance concept utilized on theCFM56-3 eliminates periodic removal of the engine forspecified inspections and overhauls and thereby reducesthe frequency of shop visits.

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VIBRATION MONITOR

CFM56 CONDITION MONITORING

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GAS PATHHEALTH

SOAPANALYSIS

LUBE PARTICLEANALYSIS

DDDDD D D D D D DDDDD DDDDDEGTR WFR HPCN HPTN

TIM

E

VIBRATIONMONITORING

BORESCOPEINSPECTION

GAMMA RAYINSPECTION


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Page 38Oct 95ALL

MAINTENANCE STRATEGY

Identification (1.A.a)The CFM56-3 engine can be separated into three majormodules, seventeen individual modules, of which ten arereplaceable under the Modular Maintenance Concept.

Improved subassembly designs within the modulesreduced a number of parts. These improvements overprevious engine designs support the CFM56-3 modularmaintenance system.

The three major modules that can be separated from theassembly to perform specific maintenance operations arethe:

- Fan major module

- Core major module

- LPT major module

This engine concept gives the maintenance personnelthe option to work on any of the three modules with aminimum amount of disassembly of the other majormodules. This modular design provides the customer acost savings for maintenance procedures.

Purpose (1.B.a)The CFM56-3 engine design is to minimize maintenancecosts and out of service time so that each maintenance

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action requires as few man hours and total elapsed timeas possible. With an advanced modular engine designand excellent accessibility of components, this conceptprovides the capability for an extensive on-wingmaintenance program.


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Page 39Oct 95ALL

ENGINE MODULES

FAN MAJOR MODULE

LPT MAJOR MODULE

CORE ENGINEMAJOR MODULE

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BASIC ENGINE DESIGNObjectives:At the completion of this section a student should be able to:.... identify the general construction features of the CFM56-3/3B/3C engine (1.A.x).


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GENERAL ENGINE CONSTRUCTION

Engine Features (1.A.a)The CFM56-3 is a high bypass, dual rotor, axial flowadvanced technology turbofan engine that features:

- A four stage integrated fan and Low PressureCompressor (LPC) booster driven by a four stageLow Pressure Turbine (LPT)

- A nine stage High Pressure Compressor (HPC)driven by a single stage High Pressure Turbine(HPT)

- Compressor airflows controlled by Variable BleedValves (VBV) located aft of the booster andVariable Stator Vanes (VSV) within the HPC frontstages

- An annular combustion chamber increases the HPCdelivery air velocity to drive both turbines

- An accessory drive system extracting energy fromthe high pressure rotor to drive the engine mountedaccessories

A pylon mounted thrust reverser provides the capabilityof reducing aircraft speed on the ground. The thrustreverser is designed, manufactured, and supported byThe Boeing Company.


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CFM56 TURBOFANS


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Frames and Bearings (1.A.a)The solid structure design is acquired by a short length, afan frame, and a turbine frame.

- The fan frame is in the front located between the fancase and core module and is a component of thefan major module.

- Turbine frame is in the rear located after the LPTcase and is a component of the LPT major module.

The rotors are supported by five main bearings that aremounted in two engine sumps of the lubricating system.

- In the forward sump of the fan frame, the No. 1 ballbearing supports thrust and radial loads while theNo. 2 roller bearing supports the radial loads of thefan and booster assembly.

- The HPC front shaft thrust and radial loads aresupported by the No. 3 ball bearing contained withinthe Inlet Gearbox (IGB) assembly.

- In the aft sump area of the LPT, the No. 4 rollerbearing supports the radial load of the HPT rearshaft on the LPT shaft.

- The No. 5 roller bearing mounted within the turbineframe supports the radial load of the LPT shaft aftend.


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ENGINE CONSTRUCTION

FAN FRAME TURBINE FRAME

5 BEARINGS

2 SUMPS

2 FRAMES


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Engine Breakdown (1.A.a)The dual rotor design of the CFM56-3 engine consists of:

The Low Pressure System:- A single stage fan, connected to a three stage

booster rotor assembly

- A single stage fan Outlet Guide Vane (OGV)assembly in the secondary airflow

- Four stage booster stator assembly in the primaryairflow

- Twelve fully controlled VBV, located in the fan framebetween booster and HPC for engine air cyclematching throughout the operating range

- Four stage LPT to drive fan and booster

The High Pressure System:- Nine stage HPC rotor

- One variable Inlet Guide Vane (IGV) assembly

- Three VSV assemblies

- Five HPC stator assemblies

- One OGV assembly (HPC stator stage 9)

- Short machined ring construction annular combustorwith 20 fuel nozzles

- A single stage HPT nozzle and rotor assembly todrive the HPC

The Accessory Drive System:- IGB

- Radial drive shaft

- Transfer Gearbox (TGB)

- Horizontal drive shaft

- Accessory Gearbox (AGB)


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CFM56 ENGINE CONSTRUCTION

ACCESSORYDRIVE

SECTIONINLET

GEARBOXTRANSFERGEARBOX

ACCESSORYGEARBOX

HPSYSTEM

LPSYSTEM

LPTSHAFT

FANSHAFT

N2

RADIALDRIVESHAFT

HORIZONTALDRIVE SHAFT

FAN AND BOOSTER

- 1 FAN STAGE- 1 FAN OGV- 1 BOOSTER IGV ASSEMBLY- 3 BOOSTER ROTOR STAGES- 3 BOOSTER STATOR STAGES- 12 VARIABLE BLEED VALVES

HP COMPRESSOR

- 9 ROTOR STAGES- 1 VARIABLE IGV- 3 VARIABLE STATOR STAGES- 5 STATIONARY STATOR STAGES

COMBUSTORSECTION

- 1 OGV ASSY- 1 ANNULAR COMBUSTOR

LP TURBINE

- 4 LPT ROTOR STAGES- 4 LPT NOZZLE STAGES

HP TURBINE

- 1 HPT NOZZLE ASSY- 1 HPT ROTOR ASSY


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Flange Identification (1.A.a)The external flanges of the engine have been assignedletter designations. The letter designations will be usedfor flange identification wherever it is necessary to beexplicit about flange location, such as positioning ofbrackets, clamps, bolts, etc. Some documents likeassembly instructions or service bulletins may use adifferent locating system.

To reduce air leakage between mating flanges and toensure proper alignment during assembly, all flangemating points are of a rabbet fit construction. However,the horizontal flanges are a butt type flange.

Horizontal flanges are identified as:- Front stator case horizontal left flange

- Front stator case horizontal right flange

The engine stator cases are a matched set and shouldnot be disassociated with other engine stator cases.


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TYPICALRABBETED

FLANGE

ENGINE FLANGES

FRONT STATORCASE HORIZONTAL

LEFT FLANGE

E H J K L M N R S T UB C DA F G P


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Sump Philosophy (1.A.a)The following are key features of the CFM56 sumpphilosophy

- The oil system is of "dry sump" design.

- It consists of an external oil tank and lubricationunit.

- Lubrication oil for the bearings is scavenged at arate equal to or greater than the supply oil.

- Scavenge oil is filtered and cooled prior to return tothe oil tank.

- Main engine bearing sumps are sealed by labyrinthtype seals and airflow across the seals.

- A pressurization and cooling chamber is createdaround the bearing sump by the use of two sets ofseals; oil and air.

- Pressurization between the oil and air seals issupplied by booster discharge air.

- The bearing sump area is vented through a rotatingair/oil separator to the center vent tube creating alow pressure chamber.

- Pressurization air, seeking the path of leastresistance, flows across the oil seals thuspreventing oil flow past the oil seals.

- Any oil that might cross the oil seals is collected inthe air seal housing and forced by thepressurization air out through cavity drain piping.

- Cavity drain fluid is carried overboard by an externaldrain system.


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SUMP PHILOSOPHY

AIRSEAL

OILSEAL

AIR TOCENTER

VENT

SCAVENGEDRAIN

OILJET

AIR TOCENTER

VENT

PRESSURIZINGPORT

ROTATINGAIR/OIL

SEPARATOR


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Aerodynamic Stations (1.A.a)The airflow path design of the CFM56-3 high bypassengine consists of two flow paths; primary andsecondary, through which the engine discharges jetvelocities.

- The Primary Airflow passes through the innerportion of the fan blades (stage 1 rotor) andcontinuing through the booster. The flow path thencontinues entering the core engine and the LPTexiting through the nacelle discharge duct.

- The Secondary Airflow passes through the outerportion of the fan blades (stage 1 rotor), OGV's andexits through the nacelle discharge duct.

Flow path aerodynamic stations have been establishedto facilitate design and development of the enginethermodynamic cycle as well as performanceassessment and monitoring.

The following are the most commonly used parameterson the CFM56-3 engine:

T12 for fan speed scheduling.T2.0 for core speed scheduling.T2.5 for VSV/VBV and fuel limiting schedules.T4.95 for flight deck indication (EGT).

Ps12 for fan and core altitude corrected speedschedules.

Ps3 for fuel limiting schedule (CDP).CBP for fuel limiting schedule.


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SECONDARY AIRFLOW 0 AMBIENT10 ENGINE ENTRANCE12 SECONDARY AIRFLOW INLET13 FAN OGV DISCHARGE14 FAN FRAME INLET15 FAN FRAME DISCHARGE

PRIMARY AIRFLOW 2.0 PRIMARY AIRFLOW INLET2.3 BOOSTER DISCHARGE AIR2.4 VBV AIR EXIT2.5 HPC INLET3.0 HPC DISCHARGE3.6 COMBUSTOR INLET4.0 COMBUSTOR DISCHARGE4.1 HPT INLET4.2 HPT DISCHARGE4.8 LPT INLET

4.95 STAGE 2 LPT INLET5.0 LPT DISCHARGE

AERODYNAMIC STATIONS

2.3 2.4 15 3.0 3.6 4.0 5.04.14.2

4.8

4.952.51314

SECONDARYAIRFLOW

PRIMARYAIRFLOW

0 1012 (SECONDARY)2.0 (PRIMARY)


EFFECTIVITY





EFFECTIVITY



AIRFLOW COOLING, PRESSURIZING, AND VENTINGObjectives:At the completion of this section a student should be able to:.... identify the airflow paths for cooling, pressurizing and venting of the CFM56-3/3B/3C engine (1.A.x).....state the purpose of the airflow paths for cooling, pressurizing and venting of the CFM56-3/3B/3C engine (1.B.x).


EFFECTIVITY



OVERVIEW

DefinitionsMain Propulsion Airstream - The total airflow through thefan.

Secondary Airflow - The airflow passing through thebypass duct (Fan Discharge).

Primary Airflow - The airflow passing through the core(Core Discharge).

Pressurizing and Cooling Airflow - Those systems usingthe main propulsive airstream as a supply and/or vent.

Purpose (1.B.a)This system of parasitic leakage is necessary to provideengine reliability and efficiency while it is being subjectedto high temperature operating conditions.


EFFECTIVITY



CORE COMPARTMENT VENTILATION

PRIMARY FLOW

SUMP VENT AIR

FAN MID-SHAFT AIR CAVITY

SECONDARY FLOW

AFTROTATING

AIR/OIL SEAL

FORWARDROTATING

AIR/OILSEPARATOR

HPTCLEARANCECONTROL

5TH STAGE HPT-LPT COOLING

COOLINGMANIFOLD

CDP CUSTOMER BLEED(4 LOCATIONS)

5TH STAGECUSTOMER

BLEED

AIR SYSTEM SCHEMATIC


EFFECTIVITY



AFT SUMP PRESSURIZING

Identification (1.A.a)The source of air is booster discharge pressure receivedthrough the four tubes that carry air radially inward frombetween struts in fan frame to HPC rotor forward stubshaft. Air flows toward aft sump between the LPT shaftand the compressor rotor air duct to the sump.

Purpose (1.B.a)Pressurizes aft sump to prevent oil loss.


EFFECTIVITY



SEE COLOR AIRFLOW CHART


EFFECTIVITY



SUMP AND GEARBOX VENTING

Identification (1.A.a)Vent air from the oil tank is routed to the forward sumpvia an external line which passes through strut No. 4 ofthe fan frame. Combined vent air from the AGB andTGB flows through the radial drive shaft housing to jointhe forward sump vent.

The rotating air/oil separator on the fan shaft allows ventair into the center vent tube for venting rearward to theprimary exhaust.

Purpose (1.B.a)To allow air to escape at a rate which will maintainadequate head pressure levels for positive action of lubeand scavenge pumps while preventing sump pressurelevels that would upset the pressure differential acrossthe oil seals.


EFFECTIVITY





EFFECTIVITY



CORE ROTOR CAVITY ("BORE") COOLING

Identification (1.A.a)Booster discharge air flows to the No. 3 bearing air/oilseal through holes in the HPC forward shaft. Rearwardthrough the HPC/HPT to the aft shaft of the HPT throughholes in the HPT aft shaft to the LPT rotor aft cavity.Exits to the primary air stream by flowing underneath thestage 4 LPT blade dovetails and by passing through agap between stage 4 LPT disk and the turbine frame.

Purpose (1.B.a)The core rotor cavity ("bore") cooling airflow does thefollowing:

- Cooling of HPC rotor aft cavity

- Cooling of HPT forward shaft cavity

- Cooling of HPT hub

- Cooling of LPT rotor aft cavity

- Cooling of 4th stage LPT rotor blade dovetails


EFFECTIVITY





EFFECTIVITY



HPT BLADE COOLING PATHWAYS

Identification (1.A.a)Refer to hot section airflow diagram on page 21 of thissection.

Purpose (1.B.a)Provide internal cooling for HPT rotor blades.


EFFECTIVITY





EFFECTIVITY



HPT NOZZLE COOLING PATHWAYS


Purpose (1.B.a)Cools the HPT nozzle.


EFFECTIVITY





EFFECTIVITY



HPT SHROUD ACTIVE CLEARANCE CONTROL


Purpose (1.B.a)Cools or heats the HPT rotor shroud.


EFFECTIVITY



HIGH PRESSURE TURBINE SHROUD CLEARANCE CONTROL AIR SUPPLY

GASKET

CLEARANCECONTROL VALVE

GASKET

CLAMP

CLAMP

CLAMP

COMBUSTION CASE

GASKET

CLAMP


EFFECTIVITY



LPT FIRST STAGE NOZZLE COOLING FLOW PATH


Purpose (1.B.a)The LPT 1st stage nozzle cooling flow does the following:

- Cools LPT first stage turbine nozzle.

- Cools the aft face of the HPT rotor and the cavitybetween the HPT and LPT rotors.

- Ventilates and cools the LPT rotor forward cavity.

- Cools LPT rotor rims, dovetails and blade roots ofstage 1, 2 and 3.


EFFECTIVITY



LOW PRESSURE TURBINE BLADE COOLING AIRFLOW

TOPRIMARYAIRFLOW

TOPRIMARYAIRFLOW

TOPRIMARYAIRFLOW

STAGE 1

STAGE 2

STAGE 3


EFFECTIVITY



LPT CASING COOLING FLOW PATH

Identification (1.A.a)Using discharge secondary air two air scoops on thethrust reverser pick up and direct fan discharge todistributors mounted on LPT case. Distributors provideair to six impingement tubes encircling the turbine case.

Purpose (1.B.a)Provides impingement cooling on the outer surface of theLPT casing to thermally stabilize the radial dimensionand seal clearances (performance). Minimizes radialoperating clearances (see CFM56-3 color air flow chart).


EFFECTIVITY





EFFECTIVITY



HOT SECTION AIRFLOW PATHWAYS

OverviewThe facing illustration shows three types of airflow withinthe hot section.

- Turbine Clearance Control (TCC).

Note: For the Turbine Clearance Control (TCC)description refer to air systems section.

- Compressor Discharge Pressure (CDP).

- Stage 5 air extraction.

Identification (1.A.a)Air for combustion enters primary and secondary swirlnozzles on the forward end of the combustor.

Cooling air for the combustor enters holes in the innerand outer liners and flows aft along the inner surfaces toprovide a film cooling effect.The HPT nozzles are cooledby CDP air that flows past the liners of the combustor.Air entering through the inner platform of the nozzlecools the forward cavity and air entering through theouter platform cools the aft cavity. The cooling air exitsthrough film cooling holes in the nozzle walls. CDP airwhich flows past the outside diameter of the HPT nozzlescools the HPT shrouds. This air exits to the primary airstream through holes in the shroud.

The inner support for the combustor/HPT nozzleprovides air passages and swirl inducer to deliver CDPair through holes in the front seal of the HPT rotor. Theair flows to the base of the HPT blades and exits throughholes in the blades.

Four external tubes carry the 5th stage air rearward andinput it into the cavity surrounding the stage 1 LPT nozzlesupport. After passing through the nozzles, the air flowsout the inner end and enters the chamber behind theHPT disk and the chamber inside the stage 1 and 2 LPTrotor disks. The air will join the primary airstream when itflows underneath the dovetails of the stage 1, 2 and 3blades.

Purpose (1.B.a)CDP is used for combustion and cooling of thecombustor, HPT rotor, HPT blades, HPT nozzles andHPT shrouds.

Stage 5 air extraction from the forward manifold of thecompressor stator case is used to cool the stage 1 LPTnozzle, HPT disk and LPT stage 1 and 2 disks.


EFFECTIVITY



HOT SECTION AIRFLOW CIRCUITS

SEEDETAIL A

DETAIL ATCCCDP

STAGE 5


EFFECTIVITY





EFFECTIVITY



FAN MAJOR MODULEObjectives:At the completion of this section a student should be able to:.... identify the major assemblies of the CFM56-3/3B/3C Fan Major Module (1.A.x).....state the purpose of the major assemblies of the CFM56-3/3B/3C Fan Major Module (1.B.x)..... locate the major assemblies of the CFM56-3/3B/3C Fan Major Module (2.A.x)..... recall the interfaces of the major assemblies of the CFM56-3/3B/3C Fan Major Module (2.B.x).


EFFECTIVITY


Page 2Oct 95ALL

INTRODUCTION

Overview (1.A.a)The fan major module consists of the fan rotor, the fanOGV, the booster rotor and stator, the No. 1 and No. 2bearing support, the IGB and No. 3 bearing support, thefan casing and the fan frame. These combinedcomponents form four individual modules:

- Fan and booster module

- No. 1 and No. 2 bearing support module

- IGB and No. 3 bearing module

- Fan frame module

72-00-01


EFFECTIVITY


Page 3Oct 95ALL

FAN MODULES

FANFRAME

MODULE

IGB AND NO. 3BEARING MODULE

NO. 1 AND NO. 2BEARING SUPPORT

MODULE

FAN ANDBOOSTERMODULE

FAN MAJOR MODULEWITH AGB

72-00-00


EFFECTIVITY


Page 4Oct 95ALL

INTRODUCTION

Overview (1.A.a)The accessory and transfer drive consists of the radialdriveshaft, the TGB, the horizontal driveshaft and theAGB. These combined components form two individualmodules:

- Accessory drive module

- TGB module

- AGB module

72-00-01


EFFECTIVITY


Page 5Oct 95ALL

ACCESSORY DRIVE MODULES

FAN MAJOR MODULEWITH AGB

TGBMODULE

AGBMODULE

72-00-00


EFFECTIVITY


Page 6Oct 95ALL

FAN AND LOW PRESSURE BOOSTER ASSEMBLY

Identification (1.A.b)The fan and booster module is a single stage fan rotor(38 blades) and a three stage axial flow compressor. Acompression stage consists of a compressor rotor stageand is followed by a compressor stator stage. The fanand booster module consists of the following principleparts:

- Spinner front cone

- Spinner rear cone

- Fan disk

- Fan blades (38)

- Low pressure booster vane assembly

- Low pressure booster rotor assembly

Purpose (1.B.b)The fan and booster module is driven by the LPT andprovides two separate air streams. The primary (orinner) air stream flows through the fan and boostersection where the air is compressed for introduction intothe HPC. The secondary (or outer) air stream ismechanically compressed by the fan as it enters theengine and is ducted to the outside of the core engine.This secondary air stream adds to the propulsive force

72-31-00

generated by the core engine. The results of thesecondary air flow produces approximately 78% of thetotal engine thrust.

Each rotor stage increases the speed of the air volumemoving the mass through each stator vane stage andcompressing the air.

Interface (2.B.b)The fan and low pressure booster module is bolted to therear outer flange of the fan disk.


EFFECTIVITY


Page 7Oct 95ALL

FAN AND BOOSTER ASSEMBLY

FAN BLADES

BOOSTER VANEASSEMBLIES

12 MOUNTINGBOLTS

SPINNERREARCONE

SPINNER FRONT CONE8 MOUNTING BOLTS3 SPINNER REMOVALSLOTS

BOOSTERROTOR

72-31-00


EFFECTIVITY


Page 8Oct 95ALL

NO. 1 AND NO. 2 BEARING SUPPORT ASSEMBLY

Identification (1.A.b)The "No. 1 and No. 2 bearing support assembly" moduleconsists of the following parts and assemblies:

- Fan shaft

- No. 1 bearing assembly

- No. 1 bearing support assembly

- No. 2 bearing assembly

- No. 2 bearing support

- Oil supply tubes assembly

- External tubing

Purpose (1.B.b)The No. 1 and No. 2 bearing support is the foundation forthe forward sump.

The No. 1 and No. 2 bearing support assembly maintainsthe principle method to support the fan and booster rotorassembly. The assembly also functions as the engineforward sump so that it will provide for proper operationof the systems (lubrication, pressurization, scavenge andventing) and coupling of the LPT shaft with the fan shaft.

72-32-00

Interface (2.B.b)The No. 1 and No. 2 bearing support assembly ispositioned by a rabbeted fit and is mounted to the fanframe. The fan shaft attaches to the fan disk at the frontflange and a coupling nut arrangement attaches the LPTshaft at the mid-length inner flange to the fan shaft.Splines of the fan shaft maintain rotational interface.


EFFECTIVITY


Page 9Oct 95ALL

NO. 1 AND NO. 2 BEARING SUPPORT ASSEMBLY

NO. 1 BEARING SUPPORT

FAN SHAFT

ROTATINGAIR/OIL

SEPARATOR

OIL SUPPLYTUBES

NO. 1 BEARING

NO. 2 BEARING SUPPORT

NO. 2 BEARING

STATIONARYAIR/OIL SEAL

72-32-00


EFFECTIVITY


Page 10Oct 95ALL

INLET GEARBOX AND NO. 3 BEARING SUPPORT

Identification (1.A.b)The IGB contains:

- A horizontal bevel gear

- A radial bevel gear

- The core engine thrust (No. 3 ball) bearing

Purpose (1.B.b)The inlet gearbox and No. 3 bearing support serves asthe mechanical coupling between the HPC and the TGB.Also, it provides support for the forward end of the coreengine.

Interface (2.B.b)The inlet gearbox and No. 3 bearing support is bolted tothe forward side of the fan frame aft flange.

72-61-00


EFFECTIVITY


Page 11Oct 95ALL

INLET GEARBOX

NO. 3 BALL BEARING

HORIZONTALBEVEL GEAR

NO. 3 BEARINGLOCKING NUT

RADIAL BEVEL GEAR

HOUSING

72-61-00


EFFECTIVITY


Page 12Oct 95ALL

FAN FRAME ASSEMBLY

Identification (1.A.b)The primary airflow to the HPC is ducted in between thecenter hub outer contour and the mid-box structure innercontour. It houses the VBV system and has provisionsfor attachment of the engine to the airframe throughengine mounts. The secondary airflow is ducted inbetween the mid-box structure outer contour and the fancase/fan frame inner contour.The fan frame module consists of the following majorparts:

- Fan frame

- Fan inlet case assembly

- Fan OGV assembly

- Tube bundles

Purpose (1.B.b)The fan frame is the major structure at the front of theengine. Its main functions are:

- To support the LPC rotor, through the No. 1 and No.2 bearing support assembly

- To support the front of the HPC rotor, through theNo. 3 bearing support

72-33-00

- To provide ducting for both the primary and thesecondary airflows

- To provide attachment for the forward enginemounts, the front handling trunnions and liftingpoints

Interface (2.B.b)The fan frame center hub accommodates the No. 1 andNo. 2 bearing support at the front and the IGB/bearingNo. 3 assembly at the back. The mid-box structuresupports the booster stator assembly at the front and theHPC stator at the back. Center hub, mid-box structureand outer case are linked by struts. The outer structurehas provisions for handling points and for installation ofequipments.


EFFECTIVITY


Page 13Oct 95ALL

FAN FRAME MODULE

PRIMARY AIRFLOW

BASIC FAN FRAMESTRUCTURE

FAN CASING

FAN FRAME ASSEMBLY

OGV AFTSUPPORTFAIRING

VBV DOOR

VBV FUELGEAR MOTOR

FAN OGV

FAN OGVASSEMBLY

SECONDARYAIRFLOW

72-33-00


EFFECTIVITY


Page 14Oct 95ALL

FAN FRAME STRUT CONFIGURATION

Identification (1.A.b)In the primary air flow path, all twelve struts have anarrow aerodynamic cross section to reduce surfacedrag to a minimum. In the secondary flowpath, thenumber of struts has been reduced to eight. The 3, 6, 9,and 12 o'clock struts have a wider cross section. Theremaining struts have the same narrow cross section asin the primary airflow struts.

All strut positions are numbered 1 through 12 ALF, (No. 1strut is in the 12 o'clock position). All 12 struts are hollowand some contain lines, sensors, or shafts.

Within strut No. 4 is the forward sump vent line tobalance all internal sump pressures. Also, within theprimary airflow path at the mid-box structure, is the No. 1bearing vibration electrical sensor cable connecting tothe accelerometer at the 9 o'clock position on the outsideof the No. 1 bearing support.

Strut No. 5 contains a housing for the N1 speed sensor.The housing is bolted to the outer diameter of the fanframe and extends to the center hub.

Strut No. 7 contains the forward sump oil scavenge line.It extends from a compartment provided in the centerhub to the outer diameter of the fan frame where it isbolted.


EFFECTIVITY


Page 15Oct 95ALL

FRONT

N1 SENSOR RING

NO. 2BEARINGSUPPORT

FAN FRAMESTRUT NO. 5

STRUT NO. 5

SECTION BB

NO. 1PROBE

HOUSING

SECTION AASTRUT NO. 7

A

B

A

1

4B

1211

10

98

76

5

32

FORWARDSUMP OIL

SCAVENGE

N1 PROBEGUIDE

SLEEVE

STRUTS

AFTLOOKINGFORWARD

N1 SENSORPROBE

FRONT

FAN FRAME STRUTS NO. 5 AND NO. 7


EFFECTIVITY


Page 16Oct 95ALL

FFAN FRAME STRUT CONFIGURATION

IdentificationStrut No. 9 contains the cavity drain for the forward sumpair/oil seals to the overboard drain system.

Strut No. 10 contains both the forward sump oil supplyline and the TGB radial drive shaft housing. The oilsupply line provides lubrication to the bearings.


EFFECTIVITY


Page 17Oct 95ALL

A

AFT LOOKINGFORWARD

STRUT NO. 10

OUTERHOUSING

FORWARD SUMP OILDISTRIBUTION MANIFOLD

FRONT

SECTION A-A

3

1 2

5

4

68

9

10

1112

A

7

A

FRONT

INNERHOUSING

FAN FRAME STRUT NO. 10

FORWARD SUMP OILSUPPLY ELBOW

TUBE

ELBOW TUBEHOUSING

FAN FRAMESTRUT NO. 10RADIAL

DRIVESHAFT

OUTER HOUSING

INNERHOUSING

OILDISTRIBUTION

MANIFOLD

FORWARD SUMPOIL SUPPLY

ELBOW TUBE

ELBOW TUBEHOUSING


EFFECTIVITY


Page 18Oct 95ALL

TUBE BUNDLE CONFIGURATION

Identification (1.A.b)Three junction box structures are mounted to the midboxstructure of the fan frame.

Purpose (1.B.b)These junction boxes are designed to isolate tubeconnections from the core engine compartment.

Location (2.A.b)The tube bundles are located at the 3, 6 and 9 o'clockpositions/ALF.


EFFECTIVITY


Page 19Oct 95ALL

VBVOPEN

P6PB

VBVCLOSE

FUEL TOMANIFOLD

PCR

VSVHEAD

VSVROD

TC2

TC1VBV

CLOSE

VSV(HEAD)

(CLOSED)

PB (CIT)

P6 (CIT)

VBV OPEN

9 O'CLOCKTUBE BUNDLE

TO LHIGNITER

PLUG

TO RHIGNITER

PLUG

TO UPPERIGNITIONEXCITER

TO UPPERIGNITIONEXCITER



(1) AFT SUMP OILSUPPLY

VBV F/B

VSV F/B

(2) CIT SENSOR DRAIN(3) LH VSV ACTUATOR DRAIN

(3) VBV MOTOR DRAIN

(1)

(3) (7)

(8)

(9)

(5)(4) (2)

(6)

PT25 MONITORING

P4.95 MONITORING

CDP (6)

FUEL MANIFOLD DRAIN (8)

HPTCCV DRAIN (7)

AFT SUMP SCAVENGE (5)

CBP (9)

COOLING AIRSUPPLY (LEADS)

TUBE BUNDLES


EFFECTIVITY



ACCESSORY DRIVE SECTION

Identification (1.A.b)The Accessory Drive Section contains:

- The Accessory Gearbox.

- The Transfer Gearbox.

Purpose (1.B.b)The main functions of the accessory drive section are:

- To provide power to the gearbox mountedaccessories

- To adapt rotational speed to the requirements ofeach individual equipment

- To convey torque from the starter to the HP rotorduring engine start

- To provide for handcranking of the HP rotor duringborescope inspection or maintenance tasks

Location (2.A.b)The AGB and TGB are located at approximately the 7:30to 9 o'clock positions.

Interface (2.B.b)The AGB is mounted to the fan frame and the TGB to thefan case. Drive power is extracted from the HPC rotor

through the IGB. A radial drive shaft (RDS) conveys thisdrive power (torque) to the TGB installed on the left-handside of the fan frame. The TGB then redirects torque toa housing drive shaft (HDS). The HDS links the TGBwith the AGB attached to the fan inlet case. The AGBmounting pads accommodate all accessories.


EFFECTIVITY


Page 21Oct 95ALL

ACCESSORY DRIVE SECTION

HYDRAULICPUMP PAD

HANDCRANKING

CONTROLALTERNATOR

TGB

RADIAL DRIVE SHAFT

LUBE UNIT

HORIZONTALDRIVE SHAFT

STARTER PAD

MAIN ENGINECONTROL

FUEL PUMPAGBIDG PAD

72-60-00


EFFECTIVITY


Page 22Oct 95ALL

THIS PAGE LEFT INTENTIONALLY BLANK

72-63-00


EFFECTIVITY



CORE MAJOR MODULEObjectives:At the completion of this section a student should be able to:.... identify the major assemblies of the CFM56-3/3B/3C Core Major Module (1.A.x).....state the purpose of the major assemblies of the CFM56-3/3B/3C Core Major Module (1.B.x)..... locate the major assemblies of the CFM56-3/3B/3C Core Major Module (2.A.x)..... recall the interfaces of the major assemblies of the CFM56-3/3B/3C Core Major Module (2.B.x).


EFFECTIVITY


Page 2Oct 95ALL

INTRODUCTION

Overview (1.A.b)The core major module consists of the rotor and statorassemblies, the combustion casing and chamber, theHPT nozzle and rotor assemblies and the HPT shroudand stage 1 LPT nozzle assembly. These combinedcomponents form eight individual modules:

- HPC rotor module

- HPC forward stator module

- HPC rear stator module

- Combustion casing module

- Combustion chamber module

- HPT nozzle module

- HPT rotor module

- HPT shroud and stage 1 LPT nozzle module

72-00-02


EFFECTIVITY


Page 3Oct 95ALL

COMBUSTIONCHAMBER

HPTNOZZLESUPPORT

HPTNOZZLE

HPTROTOR HPT SHROUD

STAGE 1 LPTNOZZLE

HPCROTOR

HPCREAR

STATOR

HPCFRONT

STATOR

COMBUSTIONCASE

CORE ENGINE COMPONENTS

72-00-02


EFFECTIVITY


Page 4Oct 95ALL

HIGH PRESSURE COMPRESSOR

Purpose (1.B.b)The compressor section provides compressor air forcombustion and bleed air from stages 5 and 9 for engineand aircraft use.

Fifth stage air is extracted through bleed manifoldsegments just aft of the stage 5 stator and is directed intoforward and aft air extraction manifolds. The forwardmanifold provides air for turbine clearance control andstage 1 LPT nozzle cooling. The aft manifold provides ableed source for aircraft use. Ninth stage air is extractedthrough a gap between the rear stator case andcombustion case (just aft of stage 9 rotor). Stage 9manifold provides the aircraft with the high pressuresource of bleed air.

72-34-00


EFFECTIVITY


Page 5Oct 95ALL

HIGH PRESSURE COMPRESSOR SECTION

CASING LINERS(FIVE PLACES)

AIR DUCTFRONT SHAFT

REAR (CDP) SEALSTAGE 4-9 SPOOL

STAGE 3 DISK

1

IGV

2 3 4 5

FRONT STATORCASE

BORESCOPE PLUGS(SIX PLACES)

STAGE 5 AIREXTRACTION

MANIFOLD

REARSTATOR

CASE STAGE 9 AIREXTRACTION

MANIFOLD

STAGE 1-2SPOOL

72-34-00


EFFECTIVITY



HIGH PRESSURE COMPRESSOR ROTOR

Identification (1.A.b)The HPC rotor is a nine stage, high speed, unitizedspool-disk structure. The rotor consists of five majorparts:

- the front shaft.

- the 1st and 2nd stage spool.

- the 3rd stage disk.

- the 4th through 9th stage spool.

- the compressor rear seal.

Interface (2.B.b)The front shaft, disk and spools are joined at a singlebolted joint to form a smooth, rigid unit.


EFFECTIVITY


Page 7Oct 95ALL

HIGH PRESSURE COMPRESSOR ROTOR

STAGE 1-2 SPOOL

STAGE 1 BLADES

STAGE 3 DISK REARROTATING

(CDP)AIR SEAL

STAGE 4-9SPOOL

STAGE 9BLADES

SHAFT

72-34-00


EFFECTIVITY


Page 8Oct 95ALL

HPC FRONT STATOR

Identification (1.A.b)The HPC front stator, consists of:

- front casing halves.

- extension casing halves.

- IGV's

- first five stages of stator vanes.

The IGV's and the 1st through 3rd stage vanes arevariable, the 4th and 5th stage vanes are fixed.

Location (2.A.b)Actuation of the variable vanes is accomplished withhydraulically actuated bellcrank assemblies mounted onthe front compressor stator at the 1:30 and 7:30 o'clockpositions.

72-35-00


EFFECTIVITY


Page 9Oct 95ALL

HIGH PRESSURE COMPRESSOR FRONT STATOR ASSEMBLY

CONFIGURATION 2

72-35-00

LEVER ARMVARIABLE VANE

ACTUATOR

CUSTOMER STAGE 5 BLEEDAIR MANIFOLD PORT

STAGE 4 AND 5 STATOR VANESEGMENTS

STAGE 5 MANIFOLD AND REARCASE SUPPORT

BELLCRANK ASSEMBLIESINLET GUIDE VANES

STAGE 1-3 VARIABLE VANES

ACTUATION RING


EFFECTIVITY


Page 10Oct 95ALL

HPC REAR STATOR

Identification (1.A.b)The HPC rear stator consists of: rear casing halves,liners, three stages of fixed vanes, and vane shrouds.

Location (2.A.b)The rear stator is located inside the front stator extensioncase.

Interface (2.B.b)It is cantilever-mounted to the rear stator support. Therear stator support outer flange is mounted between thecompressor front stator extension and the combustioncase.

72-36-00


EFFECTIVITY


Page 11Oct 95ALL

HPC REAR STATOR CASE

STATIONARY SEALS

STAGE 8 VANE SECTOR

STAGE 7VANE

SECTOR

STAGE 6VANE

SECTOR

COMPRESSOR REARSTATOR CASE

ANTI-ROTATION BAR

CONFIGURATION 2

72-36-00

STAGE 6-9 METCO 450 RUB LANDS


EFFECTIVITY


Page 12Oct 95ALL

COMBUSTION CASE

Identification (1.A.b)The combustion case is a fabricated structural weldmentit incorporates compressor OGV's and a diffuser for thereduction of combustion chamber sensitivity to thecompressor air velocity profile. It includes six borescopeports: four for inspection of the combustion chamber andtwo for inspection of the HPT nozzle.

Purpose (1.B.b)It provides structural interface, transmits engine axialloads, and provides a gas flow path between thecompressor and the LPT.

Location (2.A.b)The combustion case is located between the HPC andthe LPT.

72-41-00


EFFECTIVITY


Page 13Oct 95ALL

COMBUSTION CASE

HPT SHROUDCLEARANCE CONTROL

MIDFLANGE

BORESCOPEBOSS

(4 LOCATIONS)

CDP CUSTOMER BLEED(4 LOCATIONS)

IGNITER BOSS(2 LOCATIONS)

PS3 TAP

BOLT SHIELD

OUTLET GUIDE VANES

INDUCERVANES

HPT NOZZLEINNER SUPPORT

DIFFUSER

NUT SHIELDCDP SEAL

LPT STAGE 1 COOLING AIR(4 LOCATIONS) STAGE 5

72-41-00

FUEL NOZZLE PADS (20 LOCATIONS)BORESCOPE BOSS

(2 LOCATIONS)


EFFECTIVITY


Page 14Oct 95ALL

COMBUSTION CHAMBER

Identification (1.A.b)The combustion chamber consists of outer and innercowls, 20 primary and 20 secondary swirl nozzles, dome,and outer and inner liners.

Location (2.A.b)The combustion chamber is contained within thecombustion case.

72-42-00


EFFECTIVITY


Page 15Oct 95ALL

RING PLENUMOVERHANG

VENTURIINNER

SUPPORT RING

SECONDARYSWIRL

NOZZLE

IGNITERFERRULE

DOME RING

DEFLECTORSLEEVE

INNERLINER

INNERCOWL

DILUTION HOLES

OUTERCOWL

PRIMARYSWIRL

NOZZLE

COMBUSTION CHAMBER

OUTERLINER

COOLINGHOLES

OUTERFLANGE

DOME

INNER SUPPORTFLANGE

OUTER SUPPORT RING

72-42-00


EFFECTIVITY


Page 16Oct 95ALL

HIGH PRESSURE TURBINE NOZZLE

Identification (1.A.b)The major parts of the nozzle are 23 nozzle segments,outer support, and inner support.

Purpose (1.B.b)The high pressure turbine (HPT) nozzle is a single-stageair cooled assembly that directs the gas flow from thecombustion chamber onto the blades of the HPT rotor atthe optimum angle.

Interface (2.B.b)The high pressure turbine (HPT) nozzle mounts in thecombustion case. The aft support and seal assemblyand the aft stator seals, while not integral components ofthe HPT nozzle module are included since they attach tothe HPT stator parts.

72-51-00


EFFECTIVITY


Page 17Oct 95ALL

AFT STATOR SEALS

AFT SEALASSEMBLY

NOZZLESEGMENTS

OUTER SUPPORT

INNERSUPPORT

HIGH PRESSURE TURBINE STATOR

72-51-00


EFFECTIVITY


Page 18Oct 95ALL

HIGH PRESSURE TURBINE ROTOR

Identification (1.A.b)The rotor consists of the front shaft, the front rotating airseal, the bladed disk, and the rear shaft. The rotor isinternally cooled by low pressure compressor (booster)discharge air. It has interference rabbeted flanges forrigidity and stability. The four main structural parts aremade of high strength nickel alloys.

Purpose (1.B.b)The high pressure turbine (HPT) rotor is a single-stage,air-cooled, high efficiency turbine. The HPT rotor drivesthe high pressure compressor rotor.

Interface (2.B.b)The high pressure turbine (HPT) rotor is directlyconnected to the compressor rotor by a bolted flange toform what is essentially a single core rotor.

72-52-00


EFFECTIVITY


Page 19Oct 95ALL

HIGH PRESSURE TURBINE ROTOR

BALANCE WEIGHTREAR SHAFT

BALANCE WEIGHT

FRONTSHAFT

FRONT BLADERETAINER

BLADES

DISK

REAR BLADE RETAINER

REAR SHAFTDAMPER SLEEVE

FRONT SHAFTDAMPER SLEEVE

FRONT ROTATINGAIR SEAL

72-52-00


EFFECTIVITY


Page 20Oct 95ALL

HIGH PRESSURE TURBINE SHROUD AND STAGE 1LPT NOZZLE

Identification (1.A.b)The high pressure turbine shroud and stage 1 lowpressure turbine nozzle assembly consists of:

- the shroud/nozzle support assembly.

- HPT shrouds.

- 28 LPT stage 1 nozzle segments.

- inner air seal.

- stationary air seal.

Purpose (1.B.b)It forms the interface between the core section and theLPT module of the engine. The shroud support/nozzleassembly has a thermal response (turbine clearancecontrol) matched to the rotor to provide good tipclearance control and structural stability. The stage 1LPT nozzles direct the core engine exhaust gas onto thestage 1 LPT blades.

Location (2.A.b)The high pressure turbine (HPT) shroud and stage 1 lowpressure turbine (LPT) nozzle assembly is located insidethe aft end of the combustion case.

72-53-00

Interface (2.B.b)The forward flange of the assembly is bolted to the innersurfaces of the combustion case. The aft flange is boltedbetween the combustion case aft flange and the LPTstator forward flange.


EFFECTIVITY


Page 21Oct 95ALL

HANGERS

COOLING AIRDISTRIBUTOR

STAGE 1 LPTNOZZLE

NOZZLE INNERSHROUD

STATIONARY AIRSEAL

LEAF SEALS

HPT SHROUD AND STAGE 1 LPT NOZZLE ASSEMBLY

72-53-00

HPTSHROUD

INTEGRAL HPSHROUD/ LP NOZZLE

SUPPORT


EFFECTIVITY


Page 22Oct 95ALL

THIS PAGE LEFT INTENTIONALLY BLANK.

72-00-02


EFFECTIVITY



LOW PRESSURE TURBINE MAJOR MODULEObjectives:At the completion of this section a student should be able to:.... identify the major assemblies of the CFM56-3/3B/3C Low Pressure Turbine Major Module (1.A.x)..... locate the major assemblies of the CFM56-3/3B/3C Low Pressure Turbine Module (1.A.x).....state the purpose of the major assemblies of the CFM56-3/3B/3C Low Pressure Turbine Module (1.B.x)..... recall the interfaces of the major assemblies of the CFM56-3/3B/3C Low Pressure Turbine Module (1.B.x).


EFFECTIVITY


Page 2Oct 95ALL

INTRODUCTION

Overview (1.A.b)The LPT major module consists of the turbine shaft, thebearing No. 4 and No. 5 assemblies, LPT rotor and statorassemblies, the turbine frame and No. 5 bearing support.These combined components form three individualmodules:

- LPT shaft module

- LPT rotor and stator module

- Turbine frame module

72-00-03


EFFECTIVITY


Page 3Oct 95ALL

LPT MAJOR MODULE

LPT ROTORAND STATOR

LPT SHAFTMODULE

TURBINEFRAME

MODULE

LOW PRESSURE TURBINE MAJOR MODULE

72-00-03


EFFECTIVITY


Page 4Oct 95ALL

LPT STATOR ASSEMBLY & LPT CASE

Identification (1.A.b)This assembly consists of the LPT case, LPT shroudsupport ring, outer stationary air seal segments, thermalshields and thermal insulation blanket segments. Eachnozzle stage is identical in design.

The LPT case is a one-piece casing provided withcircular recesses in its inner diameter to accommodatenozzle and stationary air seal assemblies. The case alsofeatures:

- Nine bosses for installation of the T4.95

thermocouples

- Three bosses for installation of borescope plugsthrough LPT nozzle stages 2, 3 and 4(approximately 5 o'clock position/ALF)

- One locating pin, protruding forward on the frontflange (approximately 12 o'clock ALF)

Interface (2.B.b)Assembly starts from the front and is accomplishedtogether with rotor assembly. It is bolted with thecombustor case and the HPT shroud/LPT stage 1 nozzlesupport at the front, and is attached to the turbine frameat the back.

72-54-00


EFFECTIVITY


Page 5Oct 95ALL

LPTCASE

STAGE 2-4 LPTNOZZLES

LPT ROTOR(4 STAGES)

CONICALROTOR

SUPPORT

LOW PRESSURE TURBINE

COOLING MANIFOLDAND DISTRIBUTOR

72-54-00


EFFECTIVITY


Page 6Oct 95ALL

LOW PRESSURE TURBINE SHAFT ASSEMBLY

Identification (1.A.b)The LPT shaft assembly consists of the following majorparts:

- LPT shaft.

- LPT stub shaft.

- Center vent tube.

- Center vent tube rear extension duct.

- No. 4 roller bearing.

- No. 5 roller bearing.

The aft end is supported by the No. 5 roller bearing andthe LPT shaft houses the center vent tube of the forwardand aft engine oil sumps.

Purpose (1.B.b)The LPT shaft has two functions:

- coupling the fan booster rotor with the LPT rotor.

- providing rear support of the HPC through the No. 4roller bearing.

72-55-00

Interface (2.B.b)The LPT shaft assembly connects the fan shaft with theLPT rotor assembly at the stub shaft and conical support.


EFFECTIVITY


Page 7Oct 95ALL

CENTER VENTTUBE REAREXTENSION

DUCTREARROTATINGAIR SEAL

FORWARDROTATINGAIR SEAL

LPTSHAFT

LPTSTUB

SHAFT

LOW PRESSURE TURBINE SHAFT ASSEMBLY

72-55-00


EFFECTIVITY


Page 8Oct 95ALL

TURBINE FRAME ASSEMBLY

Identification (1.A.b)The turbine frame assembly consists of a central huband a polygonal shape outer casing. The twoconfigurations are connected by slanted struts. Thisdesign minimizes thermal stresses. These twelve hollowstruts support a midstream fairing, the exhaust plug andthe rear outer flange supports the primary exhaustnozzle. The hub inner front flange carries the No. 5bearing support.

Purpose (1.B.b)The turbine rear frame is the second of the mainstructural components. It serves as a support for theLPT rotor rear section. Also, it provides for rear enginemounting on the airframe.

72-56-00


EFFECTIVITY


Page 9Oct 95ALL

MID STREAMFAIRING

REARCOVER

TURBINEFRAME

HOUSINGSUMP

NO. 5BEARINGSUPPORT

TURBINE FRAME

72-56-00


EFFECTIVITY


Page 10Oct 95ALL

TURBINE FRAME ASSEMBLY

Interface (2.B.b)Strut No. 5 provides the scavenge pathway for oil leavingthe aft sump.

Strut No. 6 provides the supply pathway for oil going tothe aft sump.

Strut No. 7 provides the pathway for aft sump oil sealleakage to an overboard drain mast.

72-56-00


EFFECTIVITY


Page 11Oct 95ALL

TURBINE FRAME

A

OVERBOARDSEAL DRAIN

SCAVENGETUBE

OIL PRESSURETUBE

2

3

4

1112

VIEW A

REARVIEW

1

567

8

9

10

LEGENDENGINE ATCLEVIS MOUNTS

FORWARDNO. 5 STRUT NO. 6 STRUT NO. 7 STRUT

EXHAUSTPLUG

OIL SUMPCOVER

NO. 5BEARINGSUPPORT

MIDSTREAMFAIRING

FORWARD

HOUSING SUMP ANDDUAL AIR SEAL

SHROUD

HUB

OUTER CASING

LPT CASESLANTEDSTRUTS

PRIMARYEXHAUSTNOZZLE

72-56-00


EFFECTIVITY


Page 12Oct 95ALL


72-00-03


EFFECTIVITY


Page 1Oct 95GENERALALL

POWER MANAGEMENT AND ENGINE SYSTEMS INTRODUCTIONObjectives:At the completion of this section a student should be able to:.... identify the engine systems by ATA number of the CFM56-3/3B/3C engine family (1.A.x)..... identify the basic functions of power management and operational control of the CFM56-3/3B/3C engine (1.A.x).....state the purpose of the engine systems of the CFM56-3/3B/3C engine (1.B.x).


EFFECTIVITY



ENGINE SYSTEMS INTRODUCTION

Identification (1.A.a)The CFM56-3 engine systems covered in this book areidentified by the following ATA sections:

Fuel System - 73-00-00

Ignition System - 74-00-00

Air System - 75-00-00

Indicating System - 77-00-00

Oil System - 79-00-00

Purpose (1.B.a)In the fuel system, fuel is delivered to the main fuelpump via the airframe tank boost pump. The fueldelivery system contains the main fuel pump, its filter, theservo fuel heater, main fuel/oil heat exchanger, MainEngine Control (MEC), fuel manifold andfuel nozzles.

The ignition system is to produce an electrical spark toignite the fuel/air mixture in the engine combustionchamber during the starting cycle and to providecontinuous ignition during T/O, landing and operation inadverse weather conditions.

In addition to sump pressurization and internal enginecooling (see section 1) the air system provides engineoperational flexibility by means of compressor control.This is accomplished by controlling airflow to and throughthe HPC and by monitoring bleed demands.

The indicating system is to verify proper and safe engineoperation throughout the flight envelope. The engine isequipped with various sensors that monitor engineperformance. Some parameters are used directly by theaircraft crew, and others later by the maintenancepersonnel for engine performance trend monitoringpurposes.

The oil system is used for lubrication and cooling of theengine bearings and gears in the Transfer Gearbox(TGB) and Accessory Gearbox (AGB).


EFFECTIVITY



GRAPHIC TO BE DETERMINED


EFFECTIVITY



POWER MANAGEMENT AND OPERATIONALCONTROL

Identification (1.A.a)Power Management of the CFM56-3 engine consists ofboth hydromechanical (MEC) and electrical (PMC)components.

Hydromechanical units include the MEC, Fan InletTemperature sensor (T2.0), High Pressure Compressor(HPC) Inlet Air Temperature sensor (T2.5), hydraulic motorfor the Variable Bleed Valves (VBV), Turbine ClearanceControl Valve (TCCV) and Variable Stator Vane (VSV)actuators.

The MEC is mounted on the main fuel pump andprovides Actual Core Speed (N2) governing in responseto power lever input, and fuel limiting as modified byengine operational variables. The control automaticallyadjusts the VSV system through external actuators andthe VBV system through a gear motor. The MEC alsoprovides signals to operate the High Pressure TurbineClearance Control (HPTCC) system.

The MEC acceleration fuel schedule is compensated foraircraft bleeds. Thus engine acceleration time isessentially the same with bleed on or off.

The electrical units include the Power ManagementControl (PMC), control alternator, fan speed sensor, Fan

Inlet Total Air Temperature (T12) sensor and Fan InletStatic Air Pressure sensor (Ps12) [part of the PMC].

Operational control of the engine is achieved by use ofthe power lever, fuel shutoff lever and a PMC.

The PMC operates from power delivered by the controlalternator and functions to set actual Fan Speed (N1) bytrimming the MEC within narrow authority limits. WithPMC on, automatic calculation of Takeoff (T/O) N1 isaccomplished from sensed fan inlet temperature andstatic pressure signals. The power level signal is used toselect a percentage of T/O thrust; this percentage isused to establish a demanded fan speed achieved bycontrol of fuel flow through the MEC. With PMC off, theMEC provides N2 governing.


EFFECTIVITY



PMCDEACTIVATION

SWITCH

MAIN ENGINE CONTROLPOWER MANAGEMENT

CONTROL

FLIGHT DECK

PLA

TMC

TCCVTIMER

COREPARAMETERS

FANPARAMETERS

T2.0

CBP

CDP

T2.5

N2

PS12

T12

N1

WF

TC1

TC2

VSV

VBV

TC3

CONTROL SYSTEM SCHEMATIC

CONTROL PARAMETER OUTPUTS

POWERLEVER(PLA)


EFFECTIVITY





EFFECTIVITY



FUEL AND CONTROL SYSTEMObjectives:At the completion of this section a student should be able to:.... identify the components comprising the fuel system for the CFM56-3/3B/3C engine (1.A.x).....state the purpose of the fuel system for the CFM56-3/3B/3C engine (1.B.x).....state the purpose of the components comprising the fuel system for the CFM56-3/3B/3C engine (1.B.x).....describe the flow sequence of the fuel system for the CFM56-3/3B/3C engine (1.D.x)..... locate the components comprising the fuel system for the CFM56-3/3B/3C engine (2.A.x)..... identify the aircraft interfaces associated with the fuel system of the CFM56-3/3B/3C engine (2.B.x).....describe the component operation of the fuel system for the CFM56-3/3B/3C engine (2.C.x).....describe the particular component functions of the fuel system for the CFM56-3/3B/3C engine (3.D.x).


EFFECTIVITY


Page 2Oct 95ALL

FUEL DELIVERY SYSTEM

Purpose (1.A.b)The fuel delivery system performs several functions byproviding:

- The energy required for the engine thermodynamicprocess.

- Supply hydraulic power to the systems controllingthe VBV, VSV and HPTCC.

- The hydromechanical amplification necessary to theMEC.

- Cooling of the lubrication oil.

73-11-00


EFFECTIVITY


Page 3Oct 95ALL

FUEL AND COMPRESSOR CONTROL SYSTEM SCHEMATIC DIAGRAM

FUELINLET

FUEL PUMP

LP STAGE HP STAGE

FUELFILTER

WASHFILTER

SERVOFUEL

HEATER

TMC

PLA

CIT

FLOWMETER

FUELSHUTOFF

LEVER

POWERLEVER(PLA)

FUEL SUPPLY

FUEL AS CONTROL MEDIUM

ELECTRICAL TRIM

MECHANICAL LIAISON

MAIN OIL/FUELHEAT

EXCHANGER

HPTCCSYSTEM

VBV

VSV

FUELNOZZLES

PMC

MEC

T2.0

73-11-00


EFFECTIVITY


Page 4Oct 95ALL


Flow Sequence (1.D.b)Fuel from the aircraft fuel supply system enters theengine at the fuel pump inlet.

The fuel is pressurized through the Low Pressure (LP)stage of the fuel pump and flows through the main oil/fuel heat exchanger and the fuel filter.

The fuel then flows through the High Pressure (HP)stage of the pump, through the wash filter, and entersthe MEC.

Since the fuel pump has a higher fuel flow capacity thanthe fuel and control system requires, the fuel flow isdivided in the MEC into metered flow and bypass flow.

Bypass fuel is ported back to the outlet of the fuel pumpLP stage.

Metered fuel from the MEC flows through thepressurizing valve, the flowmeter, the fuel manifold, andfuel nozzles into the combustion chamber.

Some of the fuel is extracted through the pump washfilter, heated by the servo fuel heater, and supplied to theMEC to provide clean, ice-free fuel for the followingMEC servo operations:

- The MEC establishes a fuel flow (P6) to theCompressor Inlet Temperature (CIT) sensor with areturn Pb to the control. The differential fuelpressure (P6-Pb) is proportional to T2.5.

- The MEC establishes schedules for VSV and VBVpositioning.

- The MEC establishes a schedule for the TCCV as afunction of N2 speed. This then regulates the airflowof 5th and 9th stage compressor bleed air to theHigh Pressure Turbine (HPT) shroud support.Under certain T/O conditions (above 13,800 N2) theMEC will alter this schedule through the use of aTCCV timer.

- The MEC establishes a fuel flow (P7) to the T2.0

sensor with a return (Pb) to the control. Thedifferential fuel pressure (P7-Pb) is proportional toT2.0.

73-11-00


EFFECTIVITY


Page 5Oct 95ALL

FUEL PUMP

HPSTAGE

FUELSHUTOFF

LEVER

POWERLEVER

FLOWMETER

MEC

FUEL METERINGSYSTEM

BYPASSFLOW

OIL

MAIN OIL/FUELHEAT EXCHANGER

VSV ACTUATORS

VSV - VBVHYDROMECHANICAL

CONTROL

SERVOCONTROL

ASSEMBLY

FUEL INLET

BYPASSVALVE

BYPASSVALVE

FILTER

PRESSURERELIEFVALVE

BYPASSVALVE

SERVOFUEL HEATER

TCCV

NOZZLES

LP STAGE

FILTERWASH

T2.0 SENSOR


73-11-00

VBV HYDRAULICFUEL GEAR MOTOR

CIT SENSOR


EFFECTIVITY


Page 6Oct 95ALL


Identification (1.A.b)The fuel delivery System consists of:

- Fuel pump and integral filter

- Servo fuel heater

- MEC

- Fuel manifold

- Fuel nozzles.

73-11-00


EFFECTIVITY


Page 7Oct 95ALL

GRAPHIC TBD


EFFECTIVITY


Page 8Oct 95ALL

FUEL PUMP

Identification (1.A.b)The fuel pump contains a LP stage (centrifugal booststage), a integral fuel filter, a HP stage (gear stage) anda wash filter.

Purpose (1.B.b)The fuel pump pressurizes and circulates the fuelrequired for combustion and fuel-operated servo systemsthroughout the operational envelope of the engine.

Location (2.A.b)The fuel pump is mounted on the aft side of the AGB atthe 8 o'clock position.

Interface (2.B.b)The pump housing provides mounting surfaces for theMEC and the main oil/fuel heat exchanger.

Operation (2.C.b)The fuel pump is driven by the AGB through anarrangement of three splined shafts. Fuel enters thepump inlet at aircraft boost pressure. The low pressurestage prevents cavitation by increasing the aircraft boostpressure. The high pressure stage provides adequatefuel pressure to the fuel delivery system. Fuel is filteredand heated before delivery to the MEC.

73-11-00

Functional Description (3.D.b)Of the three splined shafts the main drive shaft turns theHP stage gear pump, the LP stage shaft rotates the LPimpeller pump, and the control drive shaft rotates theinternal MEC speed governor and tachometer flyweights.

The LP stage raises the fuel pressure and sends the LPstage output flow through the external main oil/fuel heatexchanger and through the fuel filter.

A filter bypass valve relieves LP stage output around thefilter if it becomes clogged.

The filtered fuel, through internal passages in the pumphousing, enters the HP stage. A pressure relief valverelieves a portion of the HP stage discharge flow back tothe HP stage inlet if HP stage discharge pressureexceeds a predetermined maximum.

The HP stage discharges through the wash filter to theMEC fuel metering system. The excess fuel is bypassfuel flow recirculating back to the outlet of the LP stage.

The fuel flow extracted through the wash filter is heatedby the servo fuel heater and then supplies the MECservos.


EFFECTIVITY


Page 9Oct 95ALL

FUEL PUMP

HP STAGERELIEF VALVE

FUEL INLET

SERVO FUEL HEATERSUPPLY PORT

MAIN DRIVE SHAFT

FILTER COVER

FILTER DRAIN PORT OUTLET PORTTO HEAT

EXCHANGER

RETURN PORTFROM HEATEXCHANGER

MOUNTING FLANGE FORATTACHMENT TO AGB

73-11-00


EFFECTIVITY


Page 10Oct 95ALL

FUEL FILTER

Identification (1.A.b)The replaceable filter element is a paper or metalcorrugated design which has a nominal filtering capabilityof 20 microns.

Purpose (1.B.b)To filter particle contaminants suspended with the fueland , protects the HP stage and the MEC from particleswithin the fuel.

Location (2.A.b)The replaceable filter element is contained in the integralfuel filter housing, located between the main oil/fuel heatexchanger and the fuel pump HP stage.

Operation (2.C.b)The fuel circulates from the outside to the inside of thefilter cartridge.

Functional Description (3.D.b)In case of a clogged filter, a bypass valve relieves fuel tothe HP stage.

73-11-00


EFFECTIVITY


Page 11Oct 95ALL

FUEL PUMP

FILTERCOVER

FILTERELEMENT

CARTRIDGE

FILTERHOUSING

O-RING

O-RING

DRAIN PLUG O-RING

BYPASS VALVE

FUEL PUMP - FUEL FILTER

73-11-00


EFFECTIVITY


Page 12Oct 95ALL

SERVO FUEL HEATER

Identification (1.A.b)The servo fuel heater consists of a housing with a heatexchanger core inside and a cover.

The core assembly is removable. It consists of a numberof aluminum alloy dimple U-shaped tubes, insertedthrough a series of drilled baffle plates. The tubes aremechanically bonded to a tube plate which is profiled tothe housing and end cover flanges. The core/housingassembly is designed to direct oil in four radial flowpasses over the fuel-filled "U" tubes.

Purpose (1.B.b)The servo fuel heater raises the temperature of the fuelto eliminate ice in the fuel before entering the controlservos, inside the MEC.

Location (2.A.b)The servo fuel heater is mounted on the aft side of themain oil/fuel heat exchanger.

73-11-00


EFFECTIVITY


Page 13Oct 95ALL

FUEL-OUTFUEL-IN

COVER

OIL-IN OIL-OUT

HOUSING

TUBE BUNDLE

ATTACHING FLANGETO MAIN OIL/FUELHEAT EXCHANGER

SERVO FUEL HEATER

73-11-00


EFFECTIVITY



SERVO FUEL HEATER

Operation (2.C.b)The servo fuel heater is a heat exchanger using theengine scavenge oil as its heat source. The hotscavenge oil first goes through the servo fuel heater andthen to the main oil/fuel heat exchanger. Within theservo fuel heater, fuel from the fuel pump wash filter isheated by the scavenge oil and then goes to the MECservos. Inside the main oil/fuel heat exchanger, fuel fromthe fuel pump LP stage cools the scavenge oil. Then thefuel goes to the inlet of the fuel filter and the cooled oilreturns to the tank.


EFFECTIVITY


Page 15Oct 95ALL

SERVO FUEL HEATER AND MAIN OIL/FUEL HEAT EXCHANGER OPERATION

73-11-00

FUEL TOFUEL FILTER

FUEL FROMFUEL PUMPLP STAGE

FUEL TO MEC SERVOS

FUELBYPASSVALVE


OIL BYPASSVALVE

OIL-IN

OIL-OUTTO TANK

SERVO FUEL HEATER

FUEL FROMFUEL PUMP

WASH FILTER


EFFECTIVITY


Page 16Oct 95ALL

MAIN ENGINE CONTROL (MEC)

Purpose (1.B.b)The MEC is a hydromechanical device that is basically aspeed governor with refinements to provide automaticspeed adjustments. This corrects for a broad variation inengine operational environments and provides additionalcontrol functions to optimize engine performance.

Location (2.A.b)The MEC is mounted to the fuel pump at approximatelythe 8 o'clock position on the aft end of the AGB.

73-21-00


EFFECTIVITY


Page 17Oct 95ALL

CFM56-3 MAIN ENGINE CONTROL (MEC)

73-21-00


EFFECTIVITY


Page 18Oct 95ALL


Operation (2.C.b)The main engine control is hydromechanical andoperates using fuel operated servo valves.

Functional Description (3.D.b)Engine speed control is effected by controlling fuel flowto maintain the flight deck speed setting and establishesthe maximum safe fuel limit under any operatingcondition. The conditions (parameters) vary, and thelimits vary accordingly to definite acceleration anddeceleration schedules. In order for the control todetermine the schedules, certain parameters such asCDP, CBP, CIT, T2.0 and N2 must be sensed. Thecontrol not only senses these parameters, but alsoamplifies and computes them and establishesacceleration and deceleration limits for fuel flow. Thecomputed limits are compared with actual fuel flow andare imposed when the limits are approached.

73-21-00


EFFECTIVITY


Page 19Oct 95ALL

MEC LEFT SIDE VIEW

VSV FEEDBACK ARM

CBP PORTCDP PORT

FUEL SHUTOFFLEVER

FULL REVERSE POWER(MINIMUM STOP)

FORWARD

POWER LEVER

FULL FORWARD POWER(MAXIMUM STOP)

CLOSED

45°10°

130°

75° OPEN

FUEL DISCHARGE PORT

IDLE BAND

VSV FEEDBACKADJUSTMENT

SCREW

VBV FEEDBACKADJUSTMENT

SCREW

VBV VALVE CLOSE SIGNAL TOVBV HYDRAULIC MOTOR PORT

VBV VALVE OPEN SIGNAL TOVBV HYDRAULIC MOTOR PORT

73-21-00


EFFECTIVITY


Page 20Oct 95ALL


Functional Description (3.D.b)A pressurizing valve maintains system pressure at lowflow conditions to ensure adequate fuel pressure forMEC servo operation and accurate fuel metering. Theschedule for VSV position is directed by fuel pump HPfuel (Pf) to the VSV actuators to position the vanes as theschedule changes. The signal which determines theposition of the VSV actuators is the result of the controlcomputing N2 and CIT specifically for this purpose. Theschedule for VBV position is directed by Pf to the VBVhydraulic motor to position the valves as a function of theVSV schedule. A bias to the normal VBV scheduleoccurs whenever the Thrust Reverser (T/R) is deployedor there is a rapid actuation of VSV toward the closedposition.

73-21-00


EFFECTIVITY


Page 21Oct 95ALL

MEC TOP VIEW

FORWARD

OVERBOARDDRAIN PORT

VSV FEEDBACK LEVER

VBV FEEDBACKCABLE BRACKET

VSV FEEDBACKCABLE BRACKET

VBV OPENEND PORT

HEATED SERVOSUPPLY PORT

VBVCLOSED

END PORT

TOP VIEW

Pcr PORT

73-21-00


EFFECTIVITY


Page 22Oct 95ALL


Functional Description (3.D.b)Scheduling the positions of the turbine clearance airvalves is created by the output of signal pressures (TC1

and TC2), which are a function of N2.

Because of a concentric shaft design, positive fuelshutoff operation is independent of power lever position.The MEC defines and regulates its own operatingpressures and returns any excess fuel supplied by thefuel pump to the downstream side of the pump LPelement.

73-21-00


EFFECTIVITY


Page 23Oct 95ALL

MEC RIGHT VIEW

A

TCCV TIMERTC3 SIGNAL

PORTTURBINE CLEARANCE

(TC1) SIGNAL PORT

TURBINECLEARANCE

(TC2) SIGNAL PORT

FORWARD

VIEW A

TORQUEMOTOR

FUEL DISCHARGE PORT

VBV FEEDBACK LEVER

P7 PORT

Pb PORTP6 PORT

VBV REVERSESIGNAL PORT

VSV HEAD PORT VSV ROD PORT IDLE SOLENOID

TO/FROM PMC

73-21-00


EFFECTIVITY


Page 24Oct 95ALL


Functional Description (3.D.b)Low Idle Adjustment - N2 Ground Idle Speed

- Adjusts the level of the ground idle flat in the MEC.This determines the N2 which will occur if the flightidle solenoid is energized (28 VDC) and the powerlever is placed in the proper position.

- Since ground idle speed is biased by CIT, a properadjustment cannot be made until the ambienttemperature (T12) is determined. Once the propertemperature is established, a reference to theappropriate schedule data chart is required.

- This adjustment does not affect any other fieldadjustment.

High Idle Adjustment - N2 Flight Idle Speed

- Adjusts the level of the flight idle flat in the MEC.This determines the N

2 speed which will occur if the

flight idle solenoid is not energized and the powerlever is placed in the proper position.

- Since the flight idle speed is biased by CIT, a properadjustment cannot be made until the ambienttemperature is determined. Once the proper

- temperature is established, a reference to theappropriate schedule data chart is required.

- A properly adjusted flight idle speed will produce apower setting that will permit acceptably quickacceleration to go-around power.


Power Trim- Physically adjusts the N2 which will occur with a

given PLA to the MEC at power lever positionsabove idle.

- Since the power lever directly controls only N2,variations in engines will cause slight differences inN1 occurring at given power lever positions with thePMC switched OFF.

- With the PMC switched ON, N2 will be modified by

the PMC to help maintain N1 for a given PLA,

temperature and ambient pressure.

73-21-00


EFFECTIVITY


Page 25Oct 95ALL

MEC ADJUSTMENTS

TAB SCREW

POWER TRIMADJUSTMENT

LOW IDLE SPEED ADJUSTMENT(SEE B FOR HIGH IDLE

SPEED ADJUSTMENT)

FUELCONTROL

BOX

FLATWASHER

PREFORMEDPACKING

HIGH IDLE SPEEDADJUSTMENT(INSIDE PORT)

MEC - BOTTOM VIEW

B

LOW IDLE SPEEDADJUSTMENT

ASSEMBLY

SCREW

SPECIFIC GRAVITYADJUSTMENT (SGA)

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EFFECTIVITY


Page 26Oct 95ALL

Ground/Flight Idle (MEC)= 1 full turn equalsapproximately 5% N2 CW (+)CCW (-)

Specific Gravity (MEC) = Set to match specific gravityfor type of fuel used:

0.82 = JET A, A1, JP-1, JP-5, JP-8

0.77 = JET B, JP-4

Power Trim (MEC) = 1 full turn equalsapproximately 1.2% N2 CW(+) CCW(-)

PLA Gain (PMC) = If PLA gain indicates between7.43 and 7.57 VDC, nocorrective action required. Ifindication is outside limits,adjust indication between7.48 and 7.52 VDC


Functional DescriptionPower Trim

- The engine is trimmed to a correct N2 with the PMCOFF. Since core speed is corrected for temperatureand pressure, a reference to the appropriateschedule of information is required.


Specific Gravity Adjustment- Used to obtain similar engine transient responses

with different types of fuel.

- Physically adjusts the pressure drop across themetering valve in the MEC. This changes thevolume flow which will occur during transientoperation (starts, rapid accels and rapid decels).This compensates for variations in heat energy perunit volume (BTU's) which will occur with variationsin fuel type.

- Adjustments should be set to the specific gravity(heat energy content) of the fuel being used.


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EFFECTIVITY


Page 27Oct 95ALL

MEC ADJUSTMENTS

TAB SCREW

POWER TRIMADJUSTMENT

LOW IDLE SPEED ADJUSTMENT(SEE B FOR HIGH IDLE

SPEED ADJUSTMENT)

FUELCONTROL

BOX

FLATWASHER

PREFORMEDPACKING

HIGH IDLE SPEEDADJUSTMENT(INSIDE PORT)

MEC - BOTTOM VIEW

B

LOW IDLE SPEEDADJUSTMENT

ASSEMBLY

SCREW

SGA

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EFFECTIVITY



SPEED GOVERNING SYSTEM

Purpose (1.B.b)The speed governing system senses physical core speed(N2) and PLA and adjusts the fuel flow (Wf) as necessaryto maintain the desired speed setting established bypower lever position (speed demand N2*).

Operation (2.C.b)The PLA speed demand is biased by Fan InletTemperature (T2.0) and Fan Inlet Pressure (Ps12), in amanner to change N2 as necessary to produce theproper fan speed (thrust).

Functional Description (3.D.b)The power lever (PLA) controlled from the flight deck, isapplied to the speed sensing governor. The speedgovernor monitors actual speed through engine drivenflyweights. The centrifugal force of the flyweights, whichis a function of engine N2 core speed, is applied to thespeed governor spring; a counteracting force is appliedby the power lever. The position of the governor pilotvalve is determined by comparing engine speed with thedesired speed setting established by the power lever Abuffer piston provides stabilization pressures to thegovernor pilot valve to prevent hunting which will causethe fuel flow to oscillate. The positioning of the governor(speed) pilot valve by the resultant difference of thepower command (power lever) and actual speed(flyweights) determines the pilot valve governor servo

command ( as limited by the pilot valve) to the governorservo piston to increase or decrease the fuel flow to thecombustion chamber and thus control speed.


EFFECTIVITY


Page 29Oct 95ALL

MEC

PLA N2

PLA

N2

Wf

FMV

FUEL

Ps12

eeeee = N2* - N2

FOR A GIVEN PLA:ÐN2* = f(T2.0 & Ps12)

N2

N2*

+

-

DESIREDSPEED

SETTING

T2.0 Ps12

Ð

T2.0

SPEED GOVERNING SYSTEM

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EFFECTIVITY


Page 30Oct 95ALL

FUEL RATE LIMITING SYSTEM

Purpose (1.B.b)Apart from the operating limits governed by themechanical integrity of its components, the engine issubject to two other limits:

1. Lower or minimum limit imposed by the risks oflean flameout.

2. Upper or maximum limit imposed by the risk of richflameout compressor flow instability (stall) andoverheating.

During transient operation, the speed governing systemcould change the metered fuel flow beyond the safe limitsdescribed above.

The purpose of the fuel limiting system is to define andimpose correct engine fuel flow limits during rapidtransients including accels, decels and starts.

Operation (2.C.b)The fuel limiting system schedules acceleration anddeceleration fuel flow to the engine as a function of N

2,

T2.5

, Ps3 and CBP.

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Functional Description (3.D.b)Three engine parameters establish the fuel rate:

- CDP or Ps3.0 (modified for bleed, CDP) - KP3.

- Compressor Inlet Tem,perature (T2.5).

- N2 core engine speed.

These 3 parameters are used to position the 3 D camand CDP cam, and through connecting linkages establishfuel flow limits. The contours of the 2 cams are designedto represent the fuel flow limits. The computing(summing/adding) levers mix the output of the two camsand compare the result to the actual fuel flow. Theresultant comparison linkage then controls the servosupply pressure to (and the drain form) the governor pilotvalve. By stopping the supply or blocking the drain, thegovernor action of positioning the fuel metering valve islimited as a function of the output of this cam andlinkage.


EFFECTIVITY


Page 31Oct 95ALL

FUEL LIMITING SYSTEM

Wf

CBP

Ps12N2CDP

MEC

PLA

Ps12

N2T2.5CDP

N2*

N2

FMV

CBP

DESIREDSPEED

SETTING

S

FUELLIMITINGSYSTEM

FUEL

T2.5

T2.0

T2.0

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EFFECTIVITY


Page 32Oct 95ALL

FUEL RATE LIMITING SYSTEM

Functional Description (3.D.b)The maximum fuel flow rate allowed during accelerationis determined by two cams:

- The "3D cam", rotated according to N2 receivedfrom the tachometer flyweights and driven linearlyaccording to T2.5. The cam position represents therequired ratio for the fuel flow rate (Wf2)/Ps3, whichvaries for each N2 and T2.5 value.

- The "CDP cam", rotated according to Ps3 and theratio Ps3/CBP.

A lever, in contact with the 3D and CDP cams, combinesboth position data in order to define the Wf2 limit allowedduring acceleration. Wf2 is compared to the actual enginefuel flow rate (Wf1). The signal resulting from Wf2-Wf1

limits fuel flow rate automatically during acceleration, forevery point within the flight envelope.

The deceleration fuel flow rate changes are 55 percent ofthe acceleration fuel flow rate changes. This is done bythe limit pilot valve control of PC and PB fuel pressuresto the governor pilot valve for deceleration versusacceleration. The deceleration fuel flow scheduleestablished at a rate which would prevent the enginefrom incurring a flameout due to too much reduction infuel flow relative to the air supplied by the high pressurecompressor.

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EFFECTIVITY


Page 33Oct 95ALL

FUEL LIMITING SYSTEM: ACCELERATION EXAMPLE

PLA

MEC

T2.0

DESIREDSPEED

SETTING

PLA

+

-

N2*

(Wf3 - Wf1)

N2

S -

Wf2/CDP

Wf2

N2T2.5

3DCAM

CDP

BLEED BIASCDP/CBPSENSOR

CBP

+-

Wf1

Wf

CDP N2Ps12T2.5

FMV

MAX.IDLE

t = 0

FUEL(Wf2 - Wf1) < (Wf3 - Wf1)

(Wf2 - Wf1)

SLS DAY

IDLE

Wf

Wf3

Wf2

Wf1

N2

FMVCAM

CDPCAM

T2.0

25

MAX.

Ps12

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EFFECTIVITY



IDLE CONTROL SYSTEM

Purpose (1.B.b)The engine idle control system is an automatic systemwhich uses the aircraft' ground sensing relay to maintainengine high idle in flight and low idle when the airplaneis on the ground.

Low idle speed for ground use will provide a constantthrust level regardless of inlet temperature and isscheduled to produce adequate taxi thrust whileminimizing noise, fuel consumption and braking effort. Inflight low idle speed is scheduled to minimize fuelconsumption.

High Idle speed is optimized to provide rapid recovery ofT/O thrust if required.

Operation (2.C.b)Only one throttle position is used regardless of whichidling speed is selected. Both idling speeds areautomatically adjusted as a function of T2.0 and Ps12.

Functional Description (3.D.b)When the PLA is at idle, the speed governing systemreceives an idle-corrected speed signal corresponding tolow or high idle. The system is designed to switch to thehigh idle schedule from the low idle schedule when a28 VDC signal is removed from the solenoid mountedon the MEC.


EFFECTIVITY


Page 35Oct 95ALL

IDLE SYSTEM

MEC

N2

AIMI

PLA

S +

SCHEDULE

SERVO-PISTON(ACTION)

SOLENOID(DE-ENERGIZE)

SERVO-PISTON(NO-ACTION)

SOLENOID(ENERGIZE)

N2

PLA

MI

AIRCRAFTCONFIGURATION

HIGH IDLESELECTION

PLA ON IDLE

N2

FMV

Ps12N2

Ps12

N2*

N2*

MIN IDLE

APPROACHIDLE

AIR FRAME

LOW IDLESELECTION

T2.0

FUEL

Wf

T2.0

T2.0

FLIGHTDECK

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EFFECTIVITY


Page 36Oct 95ALL

FUEL MANIFOLD ASSEMBLY

Identification (1.A.b)The fuel manifold is composed of two halves with athree-piece drain manifold.

Each manifold half incorporates 10 fuel nozzleconnections. The complete fuel manifold supplies fuel to20 fuel nozzles.

The drain manifold has 15 integral and 5 removabledrain tubes and is connected to each fuel nozzle. The 5removable drain tubes are to facilitate borescoping.

Purpose (1.B.b)To distribute fuel from the MEC to the fuel nozzles, andprovide drainage in the event of a leak.

Location (2.A.b)The fuel manifold is connected to a Y-shaped supplytube at approximately the 5 and 6 o'clock positions.Each connection of the Y has an individual drain tubethat is secured to the fuel manifold by bolts.

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EFFECTIVITY


Page 37Oct 95ALL

C

FUELNOZZLE

(20 PLACES)

SEE C

SEE B

B

AT NOZZLE POSITIONS1, 2, 4, 5, 7, 9, 10, 12, 13,14, 15, 16, 17, 19 AND 20

AT NOZZLE POSITIONS3, 6, 8, 11 AND 18

FUEL MANIFOLD

DRAIN MANIFOLD

FUEL MANIFOLD

DRAIN MANIFOLD

DRAIN MANIFOLD/LINE CONNECTOR

DRAIN LINE DRAIN LINE

DRAIN MANIFOLD

FUELMANIFOLD

73-11-00

FUEL MANIFOLD ASSEMBLY


EFFECTIVITY



FUEL NOZZLES

Identification (1.A.b)Each of the 20 fuel nozzles contains a primary and asecondary flow path, a flow divider, a check valve, fuelstrainers and a dual orifice spray tip.

Purpose (1.B.b)The fuel nozzles are designed to spray a fine mist of fuelinto the combustion chamber and are installed into thecombustion case at 20 locations. Each nozzle isconnected to a fuel manifold and drain manifold.

Location (2.A.b)The twenty fuel nozzles are numerically identifiedclockwise (CW) beginning just right of the 12 o'clockposition (aft looking forward).


EFFECTIVITY


Page 39Oct 95ALL

FUEL NOZZLES

73-11-00

FUEL NOZZLEPOSITION

SEE F

2019

18

17

15

16

14

1312

1 23

4

5

6

8

91011

7

AFT LOOKING FORWARD

MANIFOLD SLEEVECONNECTION THREADS

NOZZLE TUBE

NOZZLE AIRSHROUD

NOZZLE TIP

FUEL INLET

COLOR BAND

NAME PLATE

FLOW DIVIDERVALVE


EFFECTIVITY


Page 40Oct 95ALL

FUEL NOZZLES

Operation (2.C.b)During engine starting and at altitude low powerconditions when fuel flow is equally low, the flow dividervalve will close the secondary flow path thus assuring thedevelopment of system pressures high enough toproduce an adequate spray pattern even at low fuelflows.

The check valve in the primary flow path closes atshutdown and helps to maintain fuel manifold prime.

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EFFECTIVITY


Page 41Oct 95ALL

FUEL NOZZLE

73-11-00

INLET

CARTRIDGE VALVEASSEMBLY

PRIMARY BODY(METERING SET)

SECONDARY FLOW

PRIMARY FLOW

OUTLET

WEAR SLEEVE(6840023 SERIES)

SECONDARY BODY(METERING SET)

PRIMARYPLUG

OUTERTUBE

INCOMING FUELPRIMARY FLOWSECONDARY FLOW

PRIMARY STRAINER INLETSTRAINER

RESTRICTORORIFICE

INNERTUBE

CHECKVALVE


EFFECTIVITY


Page 42Oct 95ALL

FUEL NOZZLES

Functional Description (3.D.b)Introduced by service bulletins to improve upon startflameout margin, two or four nozzles were equipped witha richer primary fuel flow. These nozzles are placed oneither side of the ignition system igniters at nozzlepositions 7 and 8 (four-nozzle configurations) and 14 and15 (two-nozzle and four-nozzle configurations). Inaddition to their part numbers, the nozzles are identifiedby a color band around the nozzle body.


EFFECTIVITY



FUEL NOZZLE INSTALLATION

LEFTIGNITION

LEAD

NOZZLENO. 14

NOZZLENO. 15

LEFTIGNITER

PLUG

F

73-11-00

COLOR BAND


EFFECTIVITY



COMPRESSOR INLET TEMPERATURE (CIT)

Identification (1.A.b)The CIT sensor consists of a guarded, constant volume,gas-filled coil and a metering valve.

Purpose (1.B.b)The CIT sensor is a temperature sensor and temperaturecompensator unit for the MEC to establish parameters incontrolling VSV position, VBV position and acceleration/deceleration fuel flow schedules.

Location (2.A.b)The sensor is mounted into a port between the 5 and 6o'clock struts on the fan frame with the coil projected intothe HPC inlet airstream, just forward of the IGV's.


EFFECTIVITY


Page 45Oct 95ALL

CIT SENSOR

HOUSING

COIL GUARD

73-21-00

CIT SENSOR RETURN (Pb)

CIT SENSOR SUPPLY (P6)

MOUNTING FLANGE


EFFECTIVITY


Page 46Oct 95ALL


Operation (2.C.b)The CIT responds to the sensed primary inlet engine airtemperature and provides a hydraulic signal pressure(using fuel as a medium), which is a function of CIT, tothe MEC.

Functional Description (3.D.b)The temperature sensing coil has a constant volume;therefore, the gas pressure inside the coil is proportionalto the temperature. The coil is connected to the sensingbellows so that any change in gas pressure within thecoil changes the force on the feedback bellows andspring. The feedback bellows' force is a result of the fuelpressure inside the bellows which is controlled by themetering valve.

When CIT changes, the gas pressure inside the sensingbellows varies, thereby opening or closing the meteringvalve. The metering valve changes the fuel pressurewhich alters the force on the feedback bellows, thusbalancing the sensing bellows force. The differential fuelpressure, therefore, is proportional to the temperature atthe sensing coil. This fuel pressure is then used by theMEC as a scheduling parameter.

73-21-00


EFFECTIVITY


Page 47Oct 95ALL

CIT SENSOR (T2.5)

CIT SENSOR BLOCK DIAGRAM

P6

Pb

SENSING COIL

SENSING COIL

SENSING BELLOWS

METERINGVALVE MEC

HOUSINGP6 - Pb PROPORTIONAL TOSENSED TEMPERATURE

P6

Pb

73-21-00

REFERENCE BELLOWS

METERING VALVE

PRELOAD SPRING

SENSING BELLOWS

COILGUARD


EFFECTIVITY


Page 48Oct 95ALL


Functional DescriptionThis pressure actuates a servo system that positions theMEC's 3D cam axially. A decrease in temperature (coldshift), will decrease the pressure signal to the MEC. Theaffect is to reduce speed and position the 3D cam so thatthe VSV's will track on the open side of the schedule. Anabnormal CIT (cold shift) input could cause a compressorstall. A complete (cold shift) failure of the CIT sensorwould cause a large drop in hydraulic signal pressureand would drive the VSV schedule to its fail-safe setting(59oF).

73-21-00


EFFECTIVITY


Page 49Oct 95ALL

CIT SYSTEM

SENSING BELLOWS

CIT SENSOR

CITREG.

PRESSURE

AIRFLOW

SENSING LAND

SUPPLIEDSEPARATELY

EVACUATEDREFERENCE

BELLOWS

P6 ORIFICE

Pc

Pb

Pc

SERVO PISTON

INC. CIT

3D CAM

Pbr

P6

RESTORING SPRING

METERING VALVE

73-21-00

CIT PILOT VALVE PLUNGER


EFFECTIVITY


Page 50Oct 95ALL

COMPRESSOR DISCHARGE PRESSURE (CDP)

Purpose (1.B.b)The CDP sensor and associated computer linkagesystem establish a fuel flow schedule.

Location (2.A.b)CDP, or P

3, is piped to the MEC from a port located at

approximately 9 o'clock just aft of the fuel nozzles on thecombustion case.

Operation (2.C.b)The CDP sensor, in the MEC, converts the pneumatic(P

3) pressure to a hydraulic pressure and through the

CDP servo system rotates the Main Engine Control'sCDP cam. As CDP increases, the fuel flow schedule isincreased.

The CDP input is biased by a CBP measurement toprovide automatic resetting of the acceleration scheduleto maintain rapid acceleration times when airplane bleeddemands are large and provide adequate stall marginswhen bleed demands are lower. The CBP signalimposes a bias on the CDP sensor which changes CDPcam positioning to allow for a higher acceleration ratewhen airplane bleed rates are higher.

71-00-59


EFFECTIVITY


Page 51Oct 95ALL

CDP SENSING LINE

DETAIL A

DETAIL BJUNCTION BOX

A

71-00-59

B


EFFECTIVITY


Page 52Oct 95ALL

BLEED BIAS SENSOR

Identification (1.A.b)The system consists of a bleed bias sensor andconnecting tubing to the MEC. The sensor is a dualventuri device which senses CBP.

Purpose (1.B.b)The bleed bias sensor system provides automaticresetting of the acceleration schedule to maintain rapidacceleration rates when bleed demands are high, andenables adequate stall margins to be observed whenbleed demands are low.

75-33-00


EFFECTIVITY


Page 53Oct 95ALL

BLEED BIAS SENSOR INSTALLATION

CBP AIR TUBE9TH STAGE

FLANGE

BOLT (FOUR PLACES)

SEAL

SEAL

1

NIPPLE

BLEED BIAS SENSOR

HPC BLEED PORT

C-SEAL FLANGE GASKET

1 SEAL INSTALLED ONENGINES WITH CFMIS/B 72-319

B

WASHER (FOUR PLACES)

75-33-00


EFFECTIVITY



BLEED BIAS SENSOR

Location (2.A.b)The sensor is located in the 9th stage ducting and ismounted between the 9th stage ducting flange and the9th stage HPC bleed port at the 4 o'clock position.


EFFECTIVITY


Page 55Oct 95ALL

BLEED BIAS SENSOR SYSTEM COMPONENT LOCATION

SEE A

9TH STAGE DUCT

A

INNER VENTURI

B

B

A

A

NOTE: 9TH STAGE DUCT FLANGENOT SHOWN FOR CLARITY

B-BBLEED BIAS SENSORA-A

75-33-00

EXIT VENTURI

CBP TUBING TO MEC

BLEED BIAS SENSOR

COMBUSTIONCASE

HPC BLEEDPORT

9TH STAGE FLANGE


EFFECTIVITY


Page 56Oct 95ALL

BLEED BIAS SENSOR

Operation (2.C.b)The pressure measurement (CBP) from the venturi,which is a function of the bleed rate, is transmitted bytubing to the MEC CBP sensor and imposes a bias onthe CDP sensor which changes the CDP cam positioningto allow for a higher acceleration rate and adequate stallmargins depending on bleed demands.

75-33-00


EFFECTIVITY


Page 57Oct 95ALL

BLEED BIAS FUNCTION DIAGRAM

BLEEDAIR

PS3 (CBP)

N2 PS3 N2PS3/CBP

BLEED

NO BLEED

Wf

MU

LT

MU

LT

WF

/PS

3

PS3 (CBP)

WF/PS3 X PS3 X BLEED BIAS =Wf

75-33-00


EFFECTIVITY


Page 58Oct 95ALL

N2 SPEED SENSOR (FLIGHT DECK)

Identification (1.A.b)The sensor consists of a rotor, a stator and case withtwo-insert electrical connectors located on and driven bythe AGB shaft.

Purpose (1.B.b)The N2 speed sensor is an Alternating Current (AC)generator, whose frequency is directly proportional torotor speed, that provides signals to the N2 tachometerindicator and electrical power for the PMC.

Location (2.A.b)The N2 speed sensor is mounted on a bolt pad to thetop forward face of the AGB at the 8 o'clock position.

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EFFECTIVITY


Page 59Oct 95ALL

N2 CONTROL ALTERNATOR SPEED SENSOR INSTALLATION

A

AGB

73-21-00

SPEEDSENSORSTATOR

HOUSING

SPEEDSENSORROTOR

STARTVALVE

ELECTRICALCONNECTORS

AGBGEARSHAFT

AGB HANDCRANKING

COVER PLATE

N2 CONTROL ALTERNATORSPEED SENSOR HOUSING

CFMI CABLE TO PMC(DARK BLUE)

ELECTRICAL CONNECTORTO COCKPIT N2 GAUGE

SEE A


EFFECTIVITY


Page 60Oct 95ALL

N2 SPEED SENSOR (FLIGHT DECK)

Interface (2.B.b)The sensor is spline-mounted to the gearbox shaft by aself-locking nut. The stator and case are completelyseparable and mount directly to the gearbox housing.

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EFFECTIVITY


Page 61Oct 95ALL

N2 CONTROL ALTERNATOR SPEED SENSOR

AGB PAD

N2 CONTROL ALTERNATORSPEED SENSOR HOUSING

ROTOR

BOLT (THREE PLACES)

GEARSHAFT

O-RING

WASHER (THREE PLACES)

73-21-00

GEARSHAFTSELF-LOCKING

NUT


EFFECTIVITY


Page 62Oct 95ALL

N2 SPEED SENSOR (MEC)

Identification (1.A.b)Flyweights in the MEC are driven by a shaft and gearcoupling through the fuel pump and the engineaccessory drive system.

Purpose (1.B.b)N2 core engine speed sensing for the governor andtachometer systems of the MEC.

Operation (2.C.b)The flyweights provide a control input that is a function ofN2.

Functional Description (3.D.b)The MEC governor system utilizes this signal input asfeedback to null the power demand input as described inspeed governing. The tachometer system utilizes thissignal input to command the positioning of the turbineclearance valves (TC1, TC2, and TC3 on engines withHPTCC timer) and the rotational positioning of the 3Dcam. As N2 increases, the 3D cam initiates the openingof the VSV's and establishes the fuel flow accelerationschedule for the engine.

73-21-00


EFFECTIVITY


Page 63Oct 95ALL

MEC FLYWEIGHTS

PILOT VALVE PILOT VALVE

GOVERNORFLYWEIGHTS

TACHOMETERFLYWEIGHTS

MEC DRIVE SHAFT

73-21-00


EFFECTIVITY


Page 64Oct 95ALL

N1 SPEED SENSOR

Identification (1.A.b)The sensor consists of a rigid metal tube with a mountingflange and two-connector receptacle. Within the tube isan elastomer damper and a magnetic head sensor withtwo protruding pole pieces. When the N1 speed sensor isinstalled on the engine, only the two-connectorreceptacle and the body are visible.

Purpose (1.B.b)The N1 speed sensor is a pulse counter that senses N1

rotor speed and provides signals to the N1 tachometerindicator and PMC.

Location (2.A.b)The N1 speed sensor is mounted in strut No. 5 of the fanframe at the 4 o'clock position and is secured to the fanframe with two bolts.

Operation (2.C.b)Actual N1 fan speed is measured by speed sensorelements which provide an AC voltage whose frequencyis proportional to the fan speed.

Functional Description (3.D.b)The sensor incorporates dual sensing elements with oneelement providing N1 signal for the PMC and the otherelement providing signal to the N1 tachometer indicator.A magnetic ring mounted on the fan shaft is provided

73-21-00

with teeth. The passage of each tooth generates analternating voltage in the sensor element proportional toactual N1 speed.

Note: The sensor ring has one tooth thicker than the29 others to generate a signal of greater amplitude usedas phase reference for trim balance.


EFFECTIVITY


Page 65Oct 95ALL

N1 SPEED SENSOR

B

RECEPTACLE BODY A

A

SENSORPROBE

MOUNTINGFLANGE

ELASTOMERDAMPER

POLEPIECES

B

B

DC

SEE C


A-A B-B

SEE B

PULSEGENERATING

ROTOR

NO. 2 BEARING

A

73-21-00

N1 SPEEDSENSOR

SEE AFAN SHAFT

SENSORPROBE

SEED


EFFECTIVITY


Page 66Oct 95ALL

Ps12 PRESSURE SENSING

Identification (1.A.a)Four static ports are connected to a 1/4 inch line thatgoes to the top of the PMC, and to the MEC.

Purpose (1.B.a)Ps12 pressure sensing measures the engine inletpressure for core and fan corrected speed requirements.

Location (2.A.a)The sensors are mounted on the forward section of thefan casing at the 2:30, 5, 8 and 11 o'clock positions.

Operation (2.C.a)The Ps12 pressure is supplied to a sensor locatedinternally in the PMC. The sensor is a strain gageresistance bridge type with an amplifier network.

The same pneumatic pressure is applied to the MEC.

Functional Description (3.D.a)The PMC internal sensor accepts an air pressure input(pounds per square inch absolute [psia]) and converts itto a proportional Direct Current (DC) voltage. A 0-50MVDC differential output is generated as fan inlet airpressure of 1-20 psia is applied.

71-00-59


EFFECTIVITY


Page 67Oct 95ALL

Ps12 PRESSURE SENSING SYSTEM

TO PMC

TO MEC

71-00-59


EFFECTIVITY


Page 68Oct 95ALL

T12 TEMPERATURE SENSOR

Identification (1.A.b)The T

12 temperature sensor consists of two components,

a sensing element and a housing.

Purpose (1.B.b)To measure the engine inlet air temperature and providea proportional electrical signal to the PMC.

Location (2.A.b)Mounted on the inlet cowl at the 3 o'clock position.When the inlet cowl is separated from the engine, thesensor is stowed in a bracket on the engine fan case.

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EFFECTIVITY


Page 69Oct 95ALL

T12 TEMPERATURE SENSOR INSTALLATION

T12 PROBE

SEALANT

SEE C

T12 TEMPERATURESENSOR CONNECTOR

SEE A

C

A

STOW BRACKETPMC

FORWARD

73-21-00


EFFECTIVITY


Page 70Oct 95ALL

T12 TEMPERATURE SENSOR

Operation (2.C.b)The sensing element is a thermo resistance device. ThePMC provides the sensing element a constant currentand measures the voltage, thus the voltage is a functionof the temperature.

Functional Description (3.D.b)The sensing element consists of reference gradeplatinum wire bifilar wound on a cylindrical mandrel. Thehousing for the temperature sensing element is designedto protect the element and keep vibration to a minimum.The sensing element is located in a slot in the housingand forms a bypass for airflow. Air flowing past thehousing changes direction to enter the slot. Thisprevents foreign objects from entering the slot anddamaging the element. It also uses boundary layercontrol to ensure that the sensed temperature is the freestream temperature rather than that of the boundarylayer. The housing is designed to minimize turbulence inthe gas stream and is also designed to operate over alimited range of angle of attack.

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EFFECTIVITY


Page 71Oct 95ALL

T12 TEMPERATURE SENSOR LOCATION

SEE A

FORWARD

BOLT

WASHER

SPACER

DAMPER

DAMPER

B

B

EXIT FLOW

INCIDENCE

FORWARD

BOUNDARY LAYERREMOVAL PASSAGE

PROJECTEDCATCH AREA

EFFECTIVEINLET AREA

SENSINGELEMENTS

LIQUIDCONTAMINANTS

EXIT

B-B

A

73-21-00


EFFECTIVITY


Page 72Oct 95ALL

T2.0 FAN INLET TEMPERATURE (FIT) SENSOR

Identification (1.A.b)The helium-filled sensing element is permanentlyattached by a capillary tube to the housing containing thebellows and a variable orifice metering valve. Attachingfuel lines transmit fuel flow from the MEC through thehoused metering valve and back to the MEC.

Purpose (1.B.b)To provide a hydraulic signal (fuel pressure) to the MECproportional to the fan inlet temperature.

Location (2.A.b)The sensing element is located in the fan inlet duct atapproximately the 11 o'clock position and is inserted inthe fan inlet airstream. The bellows/valve housing ismounted on the fan case directly aft of the sensingelement.

When the fan inlet duct is separated from the engine, thesensing element is stowed on a bracket on the enginefan case.

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EFFECTIVITY


Page 73Oct 95ALL


SEE B

INLET COWL

SEALANT FORWARD

B

T2.0 ELEMENT

T2.0 TEMPERATURESENSOR ELEMENT

CAPILLARYTUBE

73-21-00


EFFECTIVITY


Page 74Oct 95ALL


Functional DescriptionHelium trapped in the sensing element cylinder, capillarytube and housed bellows will vary in pressure withchanges in inlet temperature. The change in bellowsforce will change the FMV position with back pressure inthe fuel inlet line (P

7) being developed proportionally to

the inlet temperature. The differential pressure betweenP

7 and P

b increases with increases in inlet temperature.

73-21-00


EFFECTIVITY


Page 75Oct 95ALL


PB

P7

SENSING PROBE

PRELOAD SPRING

SENSING BELLOWS

REFERENCE BELLOWS

METERING VALVE

73-21-00


EFFECTIVITY


Page 76Oct 95ALL

POWER LEVER ANGLE (PLA)

Purpose (1.B.b)The PLA provides the PMC with an electrical signalproportional to the position of the throttle-controlledpower lever on the MEC.

Location (2.A.b)It is mounted within the MEC with electrical connectionsto the PMC.

Interface (2.B.b)The power lever connecting the aircraft thrust levercables to the control has stops established during thecontrol assembly adjustments to define power leverposition limits and fuel shut-off position.

Operation (2.C.b)PLA information is transmitted to the PMC from the MECvia a Rotary Variable Differential Transducer (RVDT)located inside the MEC.

Functional Description (3.D.b)The PMC produces an excitation voltage to the PLARVDT which is the PLA transducer. As PLA is rotated,the RVDT provides an electrical relationship betweenforward and reverse, PLA thrust demand.

73-21-00


EFFECTIVITY


Page 77Oct 95ALL

POWER LEVER ANGLE (PLA)

FUELSHUTOFF

POWERLEVER

SIGNAL LINETO PMC

POWER LEVER RVDT

73-21-00


EFFECTIVITY



POWER MANAGEMENT CONTROL (PMC)

Purpose (1.B.b)Provide an electronic adjustment of the MEC to obtainoptimum power settings for takeoff, climb, and cruiseflight conditions without constant adjustment of the thrustlever by the flight crew.

Location (2.A.b)The PMC, mounted on outer surface of the fan inlet caseat approximately the 3 o'clock position.


EFFECTIVITY



PMC INSTALLATION

PMC

J2 CONNECTOR

J3 CONNECTOR

J4 CONNECTOR

Ps12

CONNECTION

GROUND STRAP

MOUNTING BOLTS(FOUR PLACES)

J5 CONNECTOR

FORWARD


EFFECTIVITY


Page 80Oct 95ALL


Operation (2.C.b)The PMC is an analog electronic supervisory controlsystem with limited authority. Primarily, it integratesinputs of N1, fan inlet temperature and pressure, andPLA, and provides signals to the MEC to modify N1 forbetter control of thrust settings.

The PMC receives information and transmits commandsthrough connectors Ps12, J2, J3, J4 and J5

73-21-00


EFFECTIVITY



PMC CONNECTORS AND ADJUSTMENT WELL LOCATION

FORWARD

ADJUSTMENTWELL COVER

J2 CONNECTOR -TO N2 CONTROL

ALTERNATORSPEED SENSOR

J4 CONNECTOR -TO FLIGHT

COMPARTMENT

J3 CONNECTOR -MEC, T12 ANDN1 SENSORS

J5 CONNECTOR -TEST

CONNECTION

SEEA

A

COVER

B

SEEB

PS12PRESSURE

PORT


EFFECTIVITY


Page 82Oct 95ALL


Functional Description (3.D.b)The PMC has a number of sections, each serving aspecific function. The operation of these functions is asfollows:

- Power for the PMC connector J2 is supplied by theN

2 control alternator speed sensor mounted on the

accessory gearbox. AC voltage is supplied to thePMC through an external variable reactor whichserves as a course DC regulator. A solid-state fineregulator then supplies the constant DC referencevoltage for all internal computations.

- To determine throttle scheduling the basic flat ratedN

1 speed demand signal is computed as a

scheduled function of sensed power lever angle(PLA). The PMC provides excitation to and signalmodulation of a rotor position transducer (RVDT)inside the MEC.

- For altitude compensation of the corrected N1 fanspeed is set by the power lever position is adjustedas a function of sensed Ps

12 pressure to give the

required altitude bias. The PMC has a self-contained pressure transducer which is suppliedfrom the Ps

12 manifold from the fan inlet.

- For speed correction the physical N1 fan speed is

sensed by the N1 speed sensor and combined with

73-21-00

inputs of T12 to provide a signal proportional tocorrected N1 fan speed. This corrected fan speed iscompared to the computed demand speed andresults in an adjustment to the torque motor currentto null the error. Input signals for fan speed (N1

actual), T12, and N1 demand (PLA) and an outputsignal for the torque motor (TMC) are transmittedthrough connection J3.

- To provide temperature limiting when T12

temperatures are beyond the flat-rated point, thedemand corrected speed is reduced to give acalculated maximum gas temperature. Thecomputed demand speed obtained from the thrustschedule, and altitude bias (Ps12), is compared to acomputed T12 function and to the minimum demandspeed selected fro use in the torque motor amplifier.

- To deactivate the PMC manually a switch controlthrough connector J4 can be used to override thetorque motor current signal to the MEC torquemotor. An amber light in the flight deck willilluminate when the PMC is in the PMC OFF mode.


EFFECTIVITY



PMC - CONTROL MODE

PLAPs12T12

N1 Ps12

N2

T12

Wf

MECPMC

PLA

TMC


EFFECTIVITY


Page 84Oct 95ALL


Functional Description- A contact closure is provided at the J4 connector

that automatically closes if a failure occurs in thePMC or in a sensor used by the PMC. When thePMC deactivates itself the appropriate INOPwarning light will illuminate. This closure will remainuntil the fault is cleared and a manual disable isreset.


EFFECTIVITY


Page 85Oct 95ALL



EFFECTIVITY


Page 86Oct 95ALL

CFMI WIRING HARNESS

Identification (1.A.b)The CFMI wiring harness is made up of two cableassemblies: the control parameter wiring harness andthe N2 control alternator speed sensor cable.

Purpose (1.B.b)These cables provide power from the N2 controlalternator speed sensor to the PMC, provide signalinformation from the N1 speed sensor, PLA, T12

temperature information to the PMC and PMC signals tothe MEC torque motor PLA.

73-21-00


EFFECTIVITY


Page 87Oct 95ALL

CFMI WIRING HARNESS INSTALLATION

SEE A

N1 SPEED SENSOR

CONTROL PARAMETERWIRING HARNESS

FORWARDAGB

PLA

PMC

N2 CONTROL ALTERNATORSPEED SENSOR CABLE

N2 CONTROL ALTERNATORSPEED SENSOR

T12

TEMPERATURESENSOR

A

73-21-00


EFFECTIVITY





EFFECTIVITY


Page 89Oct 95ALL

SPEED SENSOR CABLE INSTALLATION FOR THE N 2 CONTROL ALTERNATOR

12 O'CLOCKVIEWED DOWN

FORWARD

TGB

AGB

9 O'CLOCK

3 O'CLOCK

J2

FLANGE NO. S

PMC

IGNITIONEXCITERS

A BCD E F H J K

SEE B

SEE A

A

B

UP

UP

73-21-00

SPEED SENSOR TOTHE N2 CONTROL

ALTERNATOR


EFFECTIVITY


Page 90Oct 95ALL


73-21-00


EFFECTIVITY


Page 91Oct 95ALL

WIRING HARNESS INSTALLATION FOR THE CONTROL PARAMETER COMPONENTS

FAN CASE

T12

TEMPERATURESENSOR

BFORWARD

PMC

J3

N1 SPEED SENSOR

MOVABLECONNECTOR

CLAMPS

PLA

MEC

FLANGE NO. S

UP

AGB

6 O'CLOCKVIEWED UP

OIL TANK

UP

3 O'CLOCK

SEE A

SEE B

A

A BC D E F H J K

73-21-00


EFFECTIVITY


Page 92Oct 95ALL


73-21-00


EFFECTIVITY


Page 93Oct 95ALL

CFMI WIRING HARNESS SCHEMATIC DIAGRAM

PMC

PLA

12

34

5

12

34

5

45

1312

116

78

29

10

12

3

12

3

12

31718

166

78

2122

209

105

1119

2314

154

1224

13

12

3

J2

J3

N1 SPEEDSENSOR

TORQUE MOTOR

T12 TEMPERATURESENSOR

N2 CONTROL ALTERNATORSPEED SENSOR

G

M

73-21-00


EFFECTIVITY


Page 94Oct 95ALL


73-21-00


EFFECTIVITY



IGNITION SYSTEMObjectives:At the completion of this section a student should be able to:.... identify the components comprising the ignition system of the CFM56-3/3B/3C engine (1.A.x).....state the purpose of the ignition system of the CFM56-3/3B/3C engine (1.B.x).....state the purpose of the components comprising the ignition system of the CFM56-3/3B/3C engine (1.B.x)..... locate the components comprising the ignition system of the CFM56-3/3B/3C engine (2.A.x)..... identify the aircraft interfaces associated with the ignition system of the CFM56-3/3B/3C engine (2.B.x).....describe the component operation of the ignition system of the CFM56-3/3B/3C engine (2.C.x).....describe the particular component functions of the ignition system of the CFM56-3/3B/3C engine (3.D.x).


EFFECTIVITY


Page 2Oct 95ALL

IGNITION SYSTEM

Identification (1.A.a)The ignition system consists of an engine start switch,engine igniter selector switch, two high energy ignitionexciters or two low energy ignition exciters, two igniterplugs and two coaxial shielded ignition leads.

Purpose (1.B.a)The purpose of the system is to produce an electricalspark to ignite the fuel/air mixture in the enginecombustion chamber during the starting cycle and toprovide continuous ignition during T/O, landing andoperation in adverse weather conditions.

Operation (2.C.a)The left, right or both igniter plugs may be selectedduring the starting cycle or for continuous ignitionoperation.

74-00-00


EFFECTIVITY


Page 3Oct 95ALL

IGNITION SYSTEM

C

3 O'CLOCKSTRUT

RIGHT IGNITION LEAD (TOLOWER IGNITION

EXCITER)

VIEW C

LEFT IGNITION LEAD (TOUPPER IGNITION

EXCITER)

UPPER ANDLOWER IGNITION

EXCITERS

SPARK IGNITER SPARK IGNITER

BOLTUPPER IGNITION

EXCITER

LOWER IGNITIONEXCITER

LEFT IGNITION LEAD

RIGHT IGNITIONLEAD

GROUNDSTRAP

GROUNDSTRAPBOLT

ALF

74-00-00


EFFECTIVITY


Page 4Oct 95ALL

IGNITION POWER SUPPLY

Identification (1.A.a)The ignition power supply consists of two independentignition exciters. Each exciter has an input and outputconnector. Two types of exciters are available. Bothtypes are unidirectional.

Purpose (1.B.a)The exciters provide starting and continuous duty ignitionon demand.

Location (2.A.a)The two independent ignition exciters are mounted onthe inlet fan case with resilient shock mounts at the 2o'clock position.

Operation (2.C.a)Each exciter is capable of independent operation andalternate use of ignition circuits is recommended.Selection is made by an engine igniter selector switch inthe flight deck.

The ignition exciters operate on 108-122 volts AC,380-400 Hz input. The power is transformed, rectifiedand discharged in the form of capacitor discharge pulsesthrough the ignition leads to the igniter plugs.

Functional Description (3.D.a)The high energy output is 15-20 kv, with a spark rate of

74-00-00

two sparks per second. Energy delivered is two joulesper spark. The low energy exciter output is 14-18 kv,with a spark rate of one spark per second. Energydelivered is 1.5 joule per spark.


EFFECTIVITY


Page 5Oct 95ALL

BOND JUMPER

LOWERIGNITION EXCITER

BOND JUMPER

IGNITION LEADCONNECTOR

ELECTRICALINPUT

CONNECTOR

ELECTRICALINPUT

CONNECTOR

POWERSUPPLYCABLE

POWERSUPPLYCABLE

IGNITION LEADCONNECTOR

LEFTIGNITION

LEAD

UPPER IGNITIONEXCITER

RIGHTIGNITION

LEAD

SEE A

IGNITIONEXCITER

A

74-00-00

IGNITION POWER SUPPLY


EFFECTIVITY


Page 6Oct 95ALL

HIGH TENSION DISTRIBUTION

Identification (1.A.b)A distribution system consists of ignition leads and sparkigniters. The type 4 distribution system has button-typecontacts, spring-loaded elastomeric chamfered siliconeseals and a two-piece cooling shroud which is retainedby a clamp at the spark igniter end of the ignition lead.

Purpose (1.B.b)The high tension distribution system conducts the highvoltage electrical energy developed in the ignitionexciters to the spark igniter.

Location (2.A.b)A type 4 spark igniter is threaded into an igniter bushingat the spark igniter boss at 4 and 8 o'clock on thecombustion case.

74-20-00


EFFECTIVITY


Page 7Oct 95ALL

TYPE 4 IGNITION LEADS

74-20-00

COOLINGAIR

TYPE 4CONNECTOR

COOLINGSHROUD

CONTACTS

CAPTIVEGASKET

CHAMFEREDSILICONE SEAL

IGNITERBUSHING

SPARKIGNITER

COMBUSTIONCASE BOSS

IGNITER PLUGGASKET

SEE A


EFFECTIVITY


Page 8Oct 95ALL

IGNITION LEADS

Functional Description (3.D.b)Type 4 ignition leads are constructed of silicone insulatedwire. It has a sealed flexible conduit having a copperinner braid and a nickel outer braid. The leads connectthe spark igniter to the output connectors of the ignitionexciters. The aft ends of the leads, from the 3 o'clockstrut support bracket to the spark igniter, are cooled bybooster discharge air passing through the lead conduit.

74-20-00


EFFECTIVITY


Page 9Oct 95ALL

IGNITION LEAD INSTALLATION

COOLINGAIR SHROUD

SEE A

FORWARD

74-20-00

CHAMFEREDSILICONE

SEAL

SHROUDCLAMP

TYPE 4 IGNITION LEAD CONNECTOR

COOLINGSHROUD

A

TYPE 4IGNITION

LEADSEE B

CAGEDSPRING

ASSEMBLY

CONTACT

COUPLINGNUT

COLLAR

COOLINGAIR OUTLET

CHAMFEREDSILICONE

SEAL

B

RETAININGRING

CERAMICINSULATOR


EFFECTIVITY


Page 10Oct 95ALL

IGNITER PLUG

Identification (1.A.b)The spark igniter consists of a body, washer electrode orpin electrode, tip electrode, connector pin or contactsand ceramic insulation. The tips of the spark ignitersextend through ferrules in the outer liner into thecombustion chamber. The depth of the spark igniter intothe combustion chamber is controlled on the new type 4(S/B 72-458).

Purpose (1.B.b)Produces prompt ignition of the fuel/air mixture.

Location (2.A.b)There are two igniter plugs in bosses at the 4 and 8o'clock positions on the combustion case.

74-20-00


EFFECTIVITY


Page 11Oct 95ALL

WASHERELECTRODE

TIPELECTRODE

TIPELECTRODE

WASHER-TYPE ELECTRODEPIN-TYPE ELECTRODE

PINELECTRODES

TIP

CERAMICINSULATIONSHELL

CERAMICINSULATIONSHELL

TIP

ELECTRODES

74-20-00


EFFECTIVITY



IGNITER PLUG

Operation (2.C.b)The igniter plug operates in conjunction with a capacitordischarge-type ignition exciter that produces an electricalpotential which is applied across the gap between theplug center electrode and shell. As the potentialincreases, air at the gap ionizes. When ionizationoccurs, the high energy electrical discharge of the exciterappears as a brilliant spark across the gap. The sparkproduces prompt ignition of the fuel/air mixture andproduces sufficient heat to burn clean a fouled plug.Ignition is assured under the most adverse conditions.


EFFECTIVITY


Page 13Oct 95ALL

TYPE 4 IGNITER PLUG

TERMINAL END

ELECTRODE END

74-20-00


EFFECTIVITY


Page 14Oct 95ALL


74-00-00


EFFECTIVITY



AIR SYSTEMSObjectives:At the completion of this section a student should be able to:.... identify the components comprising the air system of the CFM56-3/3B/3C engine (1.A.x).....state the purpose of the air system of the CFM56-3/3B/3C engine (1.B.x).....state the purpose of the components comprising the air system of the CFM56-3/3B/3C engine (1.B.x)..... locate the components comprising the air system of the CFM56-3/3B/3C engine (2.A.x)..... identify the aircraft interfaces associated with the air system of the CFM56-3/3B/3C engine (2.B.x).....describe the component operation of the air system of the CFM56-3/3B/3C engine (2.C.x).....describe the particular component functions of the air system of the CFM56-3/3B/3C engine (3.D.x).


EFFECTIVITY


Page 2Oct 95ALL

HPTCC VALVE WITHOUT HPTCC TIMER

Identification (1.A.b)The HPTCC system consists of a hydraulic-actuatedvalve (HPTCCV) and connecting tubing to the MEC.

Purpose (1.B.b)To obtain maximum steady-state HPT performance andto minimize EGT transient overshoot during Takeoff.

Location (2.A.b)The High Pressure Turbine Clearance Control Valve(HPTCCV) is located on the right side of the engine justbelow the horizontal split-line of the HPC case.

Operation (2.C.b)The system uses HPC bleed air from the 5th and 9thstages. Air selection is determined as a function of N2

RPM Which results in fuel pressure signals sent from theMEC to actuate the valve. The selected bleed air isducted from the valve to a manifold surrounding the HPTshroud. The temperature of the air controls the thermalexpansion of the shroud support structure to optimize theshrouds' relative clearance to the HPT blade tips.The combination of valve positions in the MEC and theclearance control valve can result in any of the followingthree (open or closed) combinations of airflow to the HPTshroud area:

- 5th stage airflow only.

75-24-00Configuration 1

- 5th and 9th stage airflow mixture.


5th stage air is extracted from the forward 5th stagemanifold of the HPC stator case at the point where theHPTCCV mounts. 9th stage air is extracted from thecombustion case through a port adjacent to one of thefuel nozzle ports and routed forward through an externaltube to the HPTCCV.


EFFECTIVITY


Page 3Oct 95ALL

HPTCCV INSTALLATION

SEE A

AIR MANIFOLD

5TH STAGE HPCBLEED AIR PORT

TC2

TC1

FUELTUBES

FROM MECFORWARD

RIGHT VSVACTUATOR SEAL

AND SHROUD DRAIN

HPTCCV

HPTCC VALVEDRAIN ANDRIGHT VSVACTUATORSEAL ANDSHROUD

DRAIN

9TH STAGEHPC

BLEED TUBE

A

Pcr

ACTUATORVALVERODS



EFFECTIVITY



Configuration 1


Functional Description (3.D.b)Actuation of the TCC valve is controlled by the followingfuel pressure signals:

- TC1, and TC2 originate from turbine clearancevalves within the MEC. These valves are positionedby the TCCV scheduling cam as directed by thetach servo valve, which is a function of N2. Atselected speeds, TC1 and TC2 will provide outputsof either Bypass Pressure (Pb) or Case Pressure(Pc). TC1 and TC2 are supplied at all times duringengine operation to control the 5th and 9th stagevalve positions in the TCCV.

- Pcr is supplied to the TCCV from the MEC. Pcr

pressure, along with spring pressure, opposes TC1and TC

2 fuel pressure signals from the MEC to

control the 5th stage and 9th stage bleed air valves.

- The pressure relationship of the three controlpressures is P

b < P

cr < P

c.

After engine start and with the engine at low idle powersetting, the airflow to the HPT shroud is from the HPC9th stage bleed. TC

1 and TC

2 both carry P

b pressure and

are opposed by Pcr and spring pressure to maintain the

5th stage valve closed and the 9th stage valve open.

Air from the HPTCCV flows through a manifold and

enters two ports near the aft flange of the combustioncase. The air circulates around an impingementmanifold, moves through the manifold and impinges onthe support for the HPT shrouds. This air acts on theshroud support to control the expansion rate of thesupport and therefore controls the clearance between theHPT blades and HPT shroud. The air then flows throughpassageways towards the aft end of the support andjoins 5th stage cooling air entering the 1st stage LowPressure Turbine Nozzle (LPTN).

When the engine is shut down, the two position hydraulicactuator valve rods are retracted, closing the 5th andopening the 9th stage air valves.


EFFECTIVITY


Page 5Oct 95ALL

HPTCCV OPERATION SHEET 1


PCR

PB

PC

PC

PC

PB

PB

IDLECRUISE

CLIMBT.O.

TC2

TC1

PCR

5THSTAGE

9THSTAGE

TOHPTCC

MANIFOLD

MEC

HPTCCVALVE


EFFECTIVITY


Page 6Oct 95ALL


Functional DescriptionAs the engine reaches takeoff power, the scheduledbleed air to the HPT shroud is from the 9th stage of theHPC. TC1 and TC2 both carry Pb pressure and areopposed by Pcr and spring pressure to maintain the 5thstage valve closed and the 9th stage valve open.



EFFECTIVITY


Page 7Oct 95ALL


PCR

PB

PC

PC

PC

PB

PB

IDLECRUISE

CLIMBT.O.

TC2

TC1

PCR

5THSTAGE

9THSTAGE

TOHPTCC

MANIFOLD

MEC

HPTCCVALVE

75-24-00


EFFECTIVITY


Page 8Oct 95ALL


Functional DescriptionWhen the throttle is positioned for climb the scheduledbleed air to the HPT shroud is from both 5th and 9thstage of the HPC. TC1 will carry Pc pressure to open the5th stage valve while TC2 will maintain Pb pressure tokeep the 9th stage valve open. Both TC1 and TC2 areopposed by Pcr and spring pressure.

A restrictor, located at the 9th stage air extraction lineinlet to the TCC valve, reduces the air pressure beingextracted. This prevents 9th stage air introduction intothe 5th stage of the compressor when both valves areopen during climb power. This simple system eliminatesthe possibility of a stall condition due to inflow bleed.



EFFECTIVITY


Page 9Oct 95ALL


PCR

PB

PC

PC

PC

PB

PB

IDLECRUISE

CLIMBT.O.

TC2

TC1

PCR

5THSTAGE

9THSTAGE

TOHPTCC

MANIFOLD

MEC

HPTCCVALVE

75-24-00


EFFECTIVITY


Page 10Oct 95ALL


Functional DescriptionWhen the throttle is positioned for cruise the scheduledbleed air to the HPT shroud is from the 5th stage of theHPC only. TC1 will carry Pc pressure to open the 5thstage valve and TC2 will carry Pc pressure to close the9th stage valve. Both TC1 and TC2 are opposed by Pcr

and spring pressure.



EFFECTIVITY


Page 11Oct 95ALL


PCR

PB

PC

PC

PC

PB

PB

IDLECRUISE

CLIMBT.O.

TC2

TC1

PCR

5THSTAGE

9THSTAGE

TOHPTCC

MANIFOLD

MEC

HPTCCVALVE

75-24-00


EFFECTIVITY


Page 12Oct 95ALL

HPTCC VALVE WITH HPTCC TIMER

Identification (1.A.b)The HPTCC system consists of a hydraulically-actuatedtimer, timer lockout solenoid valve, HPTCCV andconnecting tubing to the MEC.

Purpose (1.B.b)To obtain maximum steady-state HPT performance andto minimize EGT transient overshoot during Takeoff.

Location (2.A.b)The High Pressure Turbine Clearance Control Valve(HPTCCV) is located on the right side of the engine justbelow the horizontal split-line of the HPC case.

Operation (2.C.b)During "hot day" T/O operation, the timer modifiesoperation of the valve by sequencing a transient airschedule over a specified time period to maintain a morenearly constant HPT blade tip clearance during theperiod of HPT rotor/stator thermal stabilization. Thismaintains turbine efficiency, and thereby decreasestransient EGT overshoot.

The system uses HPC bleed air from the 5th and 9thstages. Air selection is determined as a function of N2

RPM Which results in fuel pressure signals sent from theMEC to actuate the valve. The selected bleed air isducted from the valve to a manifold surrounding the HPT


737-300,-400/CFM56-3B-2, -3C-1 with Timer

shroud. The temperature of the air controls the thermalexpansion of the shroud support structure to optimize theshrouds' relative clearance to the HPT blade tips.

The combination of valve positions in the MEC, the TCCtimer and the TCCV can result in any of the followingthree (open and closed) combinations of airflow to theHPT shroud area:


- 5th and 9th stage airflow mixture.


5th stage air is extracted from the forward 5th stagemanifold of the HPC stator case at the point where theHPTCCV mounts. 9th stage air is extracted from thecombustion case through a port adjacent to one of thefuel nozzle ports and routed forward through an externaltube to the HPTCCV.


EFFECTIVITY



Configuration 2737-300,-400/CFM56-3B-2, -3C-1 with Timer

SEE A

TS5AIR MANIFOLD

HPTCCV INSTALLATION

ACTUATORVALVE RODS

FORWARD

A

Pcr

TS9

9TH STAGE HPC BLEED TUBE

5TH STAGE HPC BLEED AIR PORT

HPTCC VALVEDRAIN ANDRIGHT VSVACTUATORSEAL ANDSHROUD

DRAIN

RIGHT VSVACTUATORSEAL AND

SHROUD DRAIN

HPTCCV

FUEL TUBES FROM HPTCC TIMER

FUEL TUBE FROM MEC


EFFECTIVITY


Page 14Oct 95ALL

HPTCC VALVE TIMER

Identification (1.A.b)The HPTCC timer consists of a latching valve and returnspring, a timer piston and return spring, and twomaximum selector valves.

Purpose (1.B.b)The HPTCC timer is a self-locking, hydraulically-actuatedsequencing unit which controls operation of the HPTCCVduring the first 182 seconds of the CFM56-3B-2 and theCFM56-3C-1 engine operation above 95% N2 (13,800RPM)

Location (2.A.b)The HPTCC timer is located on the left fan case at the10 o'clock position.

Operation (2.C.b)The latching (or lockout) valve permits the timer toactuate only once per engine cycle (i.e., from enginestart to shutdown). The timer piston providessequencing actuation for the 5th and 9th stage bleed airvalves in the HPTCCV. The two maximum selectorvalves permit the HPTCCV to be controlled by eithernormal MEC fuel pressure signals or by timersequencing.


737-300,-400/CFM56-3B-2, -3C-1 with Timer


EFFECTIVITY


Page 15Oct 95ALL

HPTCC TIMER INSTALLATION

TC3Pc

A

FORWARD

Pb

FUEL SUPPLYLINE (REF)

TC1

HPTCC TIMERTC2

TS9

TS5

ENGINEFLANGE "E"

FORWARDBRACKET

BOLT

CFM56-3B-2 ENGINES

SEE A


737-300,-400/CFM56-3B-2, -3C-1 with Timer


EFFECTIVITY


Page 16Oct 95ALL

HPTCC VALVE TIMER LOCKOUT SOLENOID

Purpose (1.B.b)The HPTCC timer solenoid is an electronically-controlledvalve which prevents the timer from being actuated afterlift-off.

Location (2.A.b)The HPTCC timer lockout solenoid valve is located justabove the timer on the fan case at the 11 o'clockposition.

Operation (2.C.b)An air sensing relay permits a 28 VDC power supply toenergize the solenoid when an airborne condition issensed.


737-300,-400/CFM56-3B-2, -3C-1 with Timer


EFFECTIVITY


Page 17Oct 95ALL

HPTCC TIMER INSTALLATION

A

FORWARD

Pc

Pb

TC3 TIMER

HPTCC TIMER

Pb

FUEL FLOWTRANSMITTER

(REF)

TS5

TS9

TC1

TC3 MEC

FUEL SUPPLYLINE (REF)

HPTCC TIMER LOCKOUTSOLENOID VALVE

CFM56-3C-1 ENGINES

SEE A


737-300,-400/CFM56-3B-2, -3C-1 with Timer


EFFECTIVITY


Page 18Oct 95ALL


Functional Description (3.D.b)Actuation of the TCC timer and valve is controlled by thefollowing fuel pressure signals:

- TC1, TC2 and TC3 originate from turbine clearancevalves within the MEC. These valves are positionedby the TCCV scheduling cam as directed by thetach servo valve, which is a function of N2. Atselected speeds, TC1 and TC2 will provide outputsof either Bypass Pressure (Pb) or Case Pressure(Pc). TC1 and TC2 are supplied to the timer at alltimes during engine operation to control the 5th and9th stage valve positions in the TCCV. TC3 issupplied to the timer lockout solenoid valve at alltimes during engine operation. If an airbornecondition is not sensed, TC3 passes through thesolenoid valve and acts as a trigger signal when N2

reaches 95% to initiate the timer sequence.

- Pc is supplied to the timer from the MEC at all timesduring engine operation. Pc pressure holds thetimer latching valve in the latched position allowingthe timer to operate only once per start to shutdowncycle of the engine. This valve prevents the timerfrom responding to TC3 trigger signals after theinitial accel to high power, and it assures that thetimer will operate through its full cycle even if TC3

turns off during the timer sequence. The latchingvalve (in its latched position) also ports Pc pressure

to the timer piston to initiate the timer sequence.

- Pb is supplied to the timer and timer solenoid valvefrom the fuel boost pump discharge pressure port atall times during engine operation.

- Ts5 provides output of either Pc or Pb fuel pressurefrom the TCC timer to the TCCV to control actuationof the 5th stage bleed air valve. When the timer isdisarmed, Ts5 ports TC1 fuel pressure to the TCCV.

- Ts9 provides output of either Pc or Pb fuel pressurefrom the TCC timer to the TCCV to control actuationof the 9th stage bleed air valve. When the timer isdisarmed, Ts9 ports TC2 fuel pressure to the TCCV.

- Pcr is supplied to the TCCV from the MEC. Pcr

pressure, along with spring pressure, opposes Ts5

and Ts9 fuel pressure signals from the timer tocontrol the 5th stage and 9th stage bleed air valves.

- Pressure relationship of the three control pressuresis Pb < Pcr < Pc.

Conditions:- Timer "off".- Aircraft on ground.- Engine at low power.- Timer not triggered.- TC3 still at Pb pressure


737-300,-400/CFM56-3B-2, -3C-1 with Timer


EFFECTIVITY


Page 19Oct 95ALL

TCC TIMER OPERATION - SHEET 1


737-300,-400/CFM56-3B-2, -3C-1 with Timer

PB

PC

PB

PC

IDLE T/O

TC1

TC2

TC3

PB (K)

TCC SOLENOID

(DEENERGIZED)

TC3

TC2

TC1

FUEL PUMP

PC (K)

LATCHING

VALVE

(UNLATCHED)

TIMER PISTON

(RETRACTED)

0 180

TCC TIMER

MAXIMUM

PRESSURE

SELECTOR

VALVE

MAXIMUM

PRESSURE

SELECTOR

VALVE

5TH STAGE

AIR

9TH STAGE

AIR

HPT

SHROUD

TCC

VALVE

PCR

TS9

TS5

MEC

PB

PC

PB

PC

PCR


EFFECTIVITY


Page 20Oct 95ALL


Functional DescriptionTimer sequencing is accomplished by the action of Pc

pressure pushing the timer piston (against the returnspring) through its travel in 182 seconds for CFM56-3B-2and 3C-1 engines.

As the timer piston moves through its stroke, variousports in the cylinder wall are covered or uncovered whichsend Pb or Pc pressure to the maximum selector valvesto override the normal TC1 and TC2 outputs and toposition the TCCV in the desired air source mode as afunction of time.

After the timer sequence elapses, the timer becomesdisarmed, and control of the TCCV returns to the normalTC1 and TC2 signals. In order to rearm the timer, theengine must be shut down for approximately threeminutes to allow fuel to drain.

Conditions:- Timer "off".- 0 seconds.- Engine above trigger point.- Latching valve, timer piston and 9th stage air valve

about to operate.- TC3 now Pc pressure


737-300,-400/CFM56-3B-2, -3C-1 with Timer


EFFECTIVITY


Page 21Oct 95ALL



737-300,-400/CFM56-3B-2, -3C-1 with Timer

LATCHING

VALVE

(UNLATCHED)

TIMER PISTON

(RETRACTED)

0 180

TCC TIMER

PB

PC

PB

PC

IDLE T/O

TC1

TC2

TC3

PB (K)

TCC SOLENOID

(DEENERGIZED)

TC3

TC2

TC1

FUEL PUMP

PC (K)

PB

PC

MAXIMUM

PRESSURE

SELECTOR

VALVE

MAXIMUM

PRESSURE

SELECTOR

VALVE

5TH STAGE

AIR

9TH STAGE

AIR

HPT

SHROUD

TCC

VALVE

PCR

TS9

TS5

PB

PC

PCR


EFFECTIVITY


Page 22Oct 95ALL


Functional DescriptionAs the engine accelerates to T/O power and core enginespeed reaches 95% N2 (13,800 RPM), the MEC actuatesthe TCC timer.

The timer then overrides the normal MEC control signalsto begin a 182 second sequence of 8 seconds of no air(5th and 9th stage bleed air TCCV's not actuated).

Conditions:- Cycle initiated.- No air mode.- 0-7 seconds.- Higher Pc pressure has closed 9th stage air valve,

whereas normally it would be open at this RPM.


737-300,-400/CFM56-3B-2, -3C-1 with Timer


EFFECTIVITY


Page 23Oct 95ALL



737-300,-400/CFM56-3B-2, -3C-1 with Timer

PB

PC

PB

PC

IDLE T/O

TC1

TC2

TC3

PB (K)

TCC SOLENOID

(DEENERGIZED)

TC3

TC2

TC1

FUEL PUMP

PC

(K)

PB

PC

PCR

LATCHING

VALVE

(UNLATCHED)

TIMER PISTON

(ADVANCING)

0 180

TCC TIMER

MAXIMUM

PRESSURE

SELECTOR

VALVE

MAXIMUM

PRESSURE

SELECTOR

VALVE

5TH STAGE

AIR

9TH STAGE

AIR

HPT

SHROUD

TCC

VALVE

PCR

TS9

TS5


EFFECTIVITY


Page 24Oct 95ALL


Functional DescriptionConditions:

- 5th stage air.- 7-152 seconds.


737-300,-400/CFM56-3B-2, -3C-1 with Timer


EFFECTIVITY


Page 25Oct 95ALL



737-300,-400/CFM56-3B-2, -3C-1 with Timer

PB

PC

PB

PC

IDLE T/O

TC1

TC2

TC3

PB (K)

TCC SOLENOID

(DEENERGIZED)

TC3

TC2

TC1

FUEL PUMP

PC (K)

MAXIMUM

PRESSURE

SELECTOR

VALVE

MAXIMUM

PRESSURE

SELECTOR

VALVE

5TH STAGE

AIR

9TH STAGE

AIR

HPT

SHROUD

TCC

VALVE

PCR

TS9

TS5

LATCHING

VALVE

(UNLATCHED)

TIMER PISTON

(ADVANCING)

0 180

TCC TIMER

PB

PC

PCR


EFFECTIVITY






- Mixed air mode.- 152 to 180 seconds.


EFFECTIVITY


Page 27Oct 95ALL



737-300,-400/CFM56-3B-2, -3C-1 with Timer

PB

PC

PB

PC

IDLE T/O

TC1

TC2

TC3

PB (K)

TCC SOLENOID

(DEENERGIZED)

TC3

TC2

TC1

FUEL PUMP

PC (K)

MAXIMUM

PRESSURE

SELECTOR

VALVE

MAXIMUM

PRESSURE

SELECTOR

VALVE

5TH STAGE

AIR

9TH STAGE

AIR

HPT

SHROUD

TCC

VALVE

PCR

TS9

TS5

LATCHING

VALVE

(UNLATCHED)

TIMER PISTON

(ADVANCING)

0 180

TCC TIMER

PB

PC

PCR


EFFECTIVITY


Page 28Oct 95ALL



- 9th stage air mode.- At 180 seconds.- Engine at low power.- Timer cycle now complete.


737-300,-400/CFM56-3B-2, -3C-1 with Timer


EFFECTIVITY





PB

PC

PB

PC

IDLE T/O

TC1

TC2

TC3

PB (K)

TCC SOLENOID

(DEENERGIZED)

TC3

TC2

TC1

FUEL PUMP

PC (K)

PB

PC

MAXIMUM

PRESSURE

SELECTOR

VALVE

MAXIMUM

PRESSURE

SELECTOR

VALVE

5TH STAGE

AIR

9TH STAGE

AIR

HPT

SHROUD

TCC

VALVE

PCR

TS9

TS5

LATCHING

VALVE

(UNLATCHED)

TIMER PISTON

(FULL STROKE)

0 180

TCC TIMER

PB

PC

PCR


EFFECTIVITY


Page 30Oct 95ALL


Functional DescriptionThe HPTCC timer lockout solenoid valve will becomeenergized after lift-off and prevent actuation of the timerif the timer was not actuated during T/O roll. The 182second cooling sequence will not be affected by thesolenoid after it is initiated during T/O roll.

An orifice, located in the 9th stage air extraction linebetween the valve and the compressor casing extractionmanifold, reduces the 9th stage air pressure being extractedto prevent 9th stage air introduction into the 5th stage of thecompressor when both valves are open (during powerclimb).

When the engine is shut down, the two position hydraulicactuator valve rods are retracted, closing the 5th andopening the 9th stage air valves.

After 182 seconds, the timer returns control of the valve tothe normal MEC control signals until the next engineshutdown. The timer resets when the engine is shut down.

Conditions:- Aircraft airborne.- TCC solenoid energized, shutting off fuel to latching

valve.- Latching valve remains latched by constant Pc

pressure until next engine shutdown, but cannot


737-300,-400/CFM56-3B-2, -3C-1 with Timer

again latch until the aircraft is on ground and TCCde-energized..

- TCC system can only operate as per TC1 and TC2

schedule once airborne and timer timed out.


EFFECTIVITY


Page 31Oct 95ALL



737-300,-400/CFM56-3B-2, -3C-1 with Timer

LATCHING

VALVE

(UNLATCHED)

TIMER PISTON

(FULL STROKE)

0 180

TCC TIMER

PB

PC

PCR

PB

PC

PB

PC

IDLE T/O

TC1

TC2

TC3

PB (K)

TCC SOLENOID

(ENERGIZED)

TC3

TC2

TC1

FUEL PUMP

PC (K)

PB

PC

MAXIMUM

PRESSURE

SELECTOR

VALVE

MAXIMUM

PRESSURE

SELECTOR

VALVE

5TH STAGE

AIR

9TH STAGE

AIR

HPT

SHROUD

TCC

VALVE

PCR

TS9

TS5


EFFECTIVITY


Page 32Oct 95ALL

VARIABLE STATOR VANE SYSTEM

Identification (1.A.b)The system consists of two VSV hydraulic actuators, twobellcrank assemblies and linkage, and a flexiblefeedback cable.

Purpose (1.B.b)The Variable Stator Vane (VSV) actuation systemcontrols primary airflow through the HPC.

Operation (2.C.b)The VSV actuation system maintains satisfactorycompressor performance over a wide range of operatingconditions. The system varies the angle of the IGV'sand the three stages of variable vanes toaerodynamically match the LP stages of compressionwith the HP stages. This variation of vane positionchanges the effective angle at which air flows across therotor blades. The angle determines the compressioncharacteristics (direction and velocity) for any particularstage of compression. By varying the variable vaneposition in accordance with a predetermined schedule asa function of those conditions affecting compressorperformance (CIT and N

2), the critical LP stages are

automatically realigned or rematched to maintainsatisfactory airflow and compressor performance duringall engine operating conditions within the requirements ofthe system.

75-31-00


EFFECTIVITY


Page 33Oct 95ALL

VSV

FUELPLA

Ps12

+

-

N2

FMVS +-

N2*

T2.5N2

Wf

Ps12

T2.0

CBP

N2

T2.5

T2.5

MEC

VSVACTUATORS

VSV FEEDBACK SIGNAL

VSV SYSTEM

DESIREDSPEED

SETTING

T2.0

FUELLIMITINGSYSTEM

N2

CDP

CBP

VSVSCHEDULE

CDP

75-31-00


EFFECTIVITY


Page 34Oct 95ALL

VSV ACTUATOR

Identification (1.A.b)Each VSV actuator is connected through a clevis link andthe stage 3 bellcrank to a master rod which unites thebellcranks to mechanically position the actuation ringswhich control VSV angular positions.

Location (2.A.b)Two VSV actuators are mounted on the HPC forwardstator case at the 1:30 and 7:30 o'clock positions.

Operation (2.C.b)The VSV actuators are single-ended, uncushionedhydraulic cylinders, which are driven in either direction byHP fuel (Pf). The actuator rod end is sealed against fuelleakage by dual-stage preformed seals, Fuel, whichcould leak past the preformed seals, is drainedoverboard through the starter air discharge duct fitting.The piston incorporates a capped preformed packing toprevent leakage across the piston and controls stroke byinternal stops. The piston rod is ensured of dirt-freeoperation by means of a wiper which cleans the rod as itretracts past the dual-stage seals. The rod end isthreaded and fitted with an adjustable extension thatincludes a clevis for connection to the VSV bellcrankassembly.

75-31-00


EFFECTIVITY


Page 35Oct 95ALL

VSV ACTUATOR CROSS SECTION

DUAL-STAGEPREFORMED

SEALS

HEX

THREADS

DRAIN

ROD ENDPORT

HEAD ENDPORT

ROD

SCRAPER

DRAIN PORT(PLUGGED ON LEFT

VSV ACTUATOR)

BODYASSEMBLY

PISTON

75-31-00


EFFECTIVITY



VSV BELLCRANK ASSEMBLY

Identification (1.A.b)Each VSV bellcrank assembly consists of four bellcranks(Inlet Guide Vane (IGV), stage 1, stage 2 and stage 3)which are mechanically driven by the VSV actuatorthrough connections to the master rod. Adjustable links,consisting of a tie rod and bearing, connect eachbellcrank to the actuation rings.


EFFECTIVITY


Page 37Oct 95ALL

VSV ACTUATION SYSTEM COMPONENTS

RIGHT VSV ACTUATOR

ADJUSTABLELINK

STAGE 2BELLCRANK

STAGE 1BELLCRANK

ADJUSTABLELINK

STAGE 3BELLCRANK

ADJUSTABLELINK

IGVBELLCRANK

VSVACTUATOR

HEAD END

ROD END

FORWARD

MASTERROD

CLEVISLINK

FEEDBACK CABLE

VSVDRAIN

LEFT VSV ACTUATOR

FORWARD

STAGE 1BELLCRANK

ROD END

ADJUSTABLELINK

ADJUSTABLELINK

IGVBELLCRANK

MASTERROD

STAGE 2BELLCRANK

HEAD END

VSVACTUATOR

CLEVISLINK

ADJUSTABLELINK

STAGE 3BELLCRANK

VSVDRAIN

75-31-00


EFFECTIVITY



VSV ACTUATION HALF RING

Identification (1.A.b)The actuation rings, are connected by actuation ringconnectors at the horizontal split-line of the compressorcasing.

Operation (2.C.b)The actuation rings rotate circumferentially about thehorizontal axis of the compressor. Movement of therings is transmitted to the individual vanes through vaneactuating lever arms.


EFFECTIVITY


Page 39Oct 95ALL

VSV BELLCRANK ASSEMBLY AND ACTUATION HALF RINGS

AFORWARD

ACTUATION RING

VSV BELLCRANK ASSEMBLY

ACTUATION RINGCONNECTOR

LEVER ARMSTAGE

3STAGE

2STAGE

1IGV

SEE A

75-31-00

LEFT VSV ACTUATOR


EFFECTIVITY


Page 40Oct 95ALL

VSV FEEDBACK CABLE

Identification (1.A.b)The VSV feedback cable is connected to the MEC leveron the aft side.

Purpose (1.B.b)VSV feedback cable movement transmits the position ofthe VSV's to the MEC.

Location (2.A.b)It is routed up through the rear portion of the 6 o'clockfan frame strut area. It connects to the bellcrank of theVSV actuator located at the 8 o'clock position on thecompressor case.

75-31-00


EFFECTIVITY


Page 41Oct 95ALL

ROUTING OF FEEDBACK CABLE (VSV)

A

MEC

DETAIL A

VSVFEEDBACK

CABLE

BRACKET

VBVFEEDBACK

CABLE

VBVFEEDBACK

CABLE

LOOPCLAMP

BRACKET

LOOPCLAMP

VSVFEEDBACK

CABLE

DETAIL B

LOOP CLAMPS

LOOPCLAMP

B

A

75-31-00

VSVFEEDBACK

CABLE


EFFECTIVITY


Page 42Oct 95ALL

VSV SYSTEM

Operation (2.C.b)The VSV's are positioned by two VSV actuators whichare operated by fuel pressure from the MEC.

Functional Description (3.D.b)In the MEC are a VSV scheduling 3D cam, which ispositioned by N2 and CIT signals, a VSV feedbackmechanism which transmits actual vane position to thecontrol, and a VSV pilot valve, which is positioned as aresult of the comparison of the scheduling cam positionand the feedback signal.

Changes in N2 rotate the 3D scheduling cam, whilechanges in CIT axially translate the cam. Movement ofthe cam repositions the pilot valve. The pilot valve portsHP fuel (main fuel pump discharge pressure) to either thehead end or rod end port of the VSV actuators, and ventsthe other end to bypass pressure. The feedbackmechanism in the control repositions the pilot valve tostabilize the actuator signal when the vanes reach thescheduled position.

HP fuel supplied to the head end port of the VSVactuator causes the piston rod to move aft (extendedposition), which in turn drives the master rod to positionthe IGV and stage 3 bellcrank upward (or downward onthe right VSV actuator) and the stage 1 and stage 2bellcranks downward (or upward on the right VSV

actuator). Movement of the bellcranks is transmitted tothe actuation rings and thus to the individual vanescausing the vanes to close.

HP fuel supplied to the rod end port causes the pistonrod to move forward (retracted position), which in turndrives the master rod to position the IGV and stage 3bellcranks downward (or upward on the right VSVactuator) and the stage 1 and stage 2 bellcranks upward(or downward on the right VSV actuator). Movement ofthe bellcranks is transmitted to the actuation rings andthus to the individual vanes causing the vanes to open.

75-31-00


EFFECTIVITY


Page 43Oct 95ALL

VSV STEADY-STATE TRACKING SCHEDULE (TYPICAL)

INCREASEDECREASE

VS

V S

TA

GE

1 -

DE

GR

EE

S

OP

EN

CLOSED LIMIT

CORRECTED CORE SPEED - N2K25 - RPM

CLO

SE

D

NOTE: THIS CURVE IS INTENDED ONLY TO PROVIDE A GENERAL VISUALPRESENTATION OF VSV OPERATION AS A FUNCTION OF ENGINE SPEED.USE MAINTENANCE MANUAL TABLE FOR SPECIFIC LIMITS.

75-31-00

OPEN LIMIT


EFFECTIVITY


Page 44Oct 95ALL

VARIABLE BLEED VALVE SYSTEM

Identification (1.A.b)The VBV system includes the following:

- A power unit consisting of a fuel-powered hydraulicgear motor supplied by fuel from the HP pump asscheduled by an external signal.

- A bleed valve stop mechanism

- A bleed valve and master ballscrew actuator unitconsisting of a speed reduction gearbox and aballscrew actuator linked to a bleed valve door

- Eleven bleed valve and ballscrew actuator units.Each unit has a speed reduction gearbox and aballscrew actuator linked to a bleed valve door.

- A bleed valve main flexible shaft installed betweenthe bleed valve and master ballscrew actuator andthe fuel gear motor

- Eleven bleed valve flexible shafts installed betweenthe bleed valve and ballscrew actuators and theflexible shaft relays.

- A flexible feedback cable to transmit to the MEC theposition of the bleed valve system.

75-32-00

Purpose (1.B.b)The VBV system performs four primary functions:

- Positions the bleed valves in response to adifferential fuel pressure through the fuel gearmotor.

- Mechanically synchronizes the bleed valvesthroughout the stroke.

- Limits the bleed valve position at the end of eachstroke.

- Provides feedback of the bleed valve position.


EFFECTIVITY


Page 45Oct 95ALL

VBV SYSTEM

PLA

Ps12

DESIREDSPEED

SETTING

S -+

N2*

N2

FMV

FUEL

FUELLIMITINGSYSTEM CBP

CDP

MEC

VSVSCHEDULE

VBVSCHEDULE

Ps12

Wf

CBP

CDP

N2T2.5

VSV VBV

VSV FEEDBACK SIGNALVBV FEEDBACK SIGNAL

FUEL GEARMOTOR

T2.0

+

-

T2.5N2

T2.0

VSVACTUATORS

75-32-00


EFFECTIVITY




Operation (2.C.b)When the bleed valves are open, a portion of the primaryairflow from the booster (Low Pressure Compressor(LPC)) is permitted to go through the midbox and into thesecondary (fan) airflow. The bleed valves open duringlow and transient operations to increase the boostermass flow and to improve booster and HPC matching.


EFFECTIVITY


Page 47Oct 95ALL

VBV SYSTEM

VSVFEEDBACK

SIGNAL

FUEL GEARMOTOR

VBVSCHEDULE

MEC

VBVFEEDBACK

CABLE

VBVFEEDBACK

ROD

VBV FEEDBACKREVERSER ARM

OVERBOARDDRAIN

STOPMECHANISM

FORWARD

BLEED VALVE ANDMASTER BALLSCREW

ACTUATOR

BLEED VALVE ANDBALLSCREW ACTUATOR

(11 UNITS)

75-32-00


EFFECTIVITY


Page 48Oct 95ALL


Functional Description (3.D.b)A hydromechanical computer, integral within the MEC,determines the bleed schedule as a function of theangular setting of the variable compressor stator atsteady-state operation and during acceleration. Thebleed valve schedule is biased to open more toward theopen side of the schedule during rapid decelerations orT/R operation.

The VBV actuation system provides an angular outputthrough the fuel gear motor, master ballscrew actuator and11 ballscrew actuators. The system is interconnected by 11flexible shafts. There are 11 ferrules installed in the fanframe struts to provide support for the flexible shafts. Thesystem is designed to open, close or modulate the 12 VBV'sto an intermediate position in response to an inputcommand signal. The VBV's remain fully synchronizedthroughout their complete stroke by the continuousmechanical flexible shaft arrangement. The MEC suppliesHP fuel to hydraulically operate the VBV actuation system.The master ballscrew actuator and the corresponding bleedvalve are connected to the MEC by a push-pull feedbackcable. The feedback cable provides VBV position bias tothe MEC.

75-32-00


EFFECTIVITY


Page 49Oct 95ALL

BLEED VALVE ANDBALLSCREW ACTUATOR

(11 UNITS) BLEED VALVEFUEL GEAR MOTOR

FORWARD

FEEDBACKREVERSER

ARM


ACTUATOR

BLEED VALVESTOP MECHANISM

FEEDBACKLEVER

FEEDBACKROD

FEEDBACKCABLE

SEE A


FLEXIBLE SHAFTS(11 UNITS)

A

75-32-00


EFFECTIVITY



VBV FUEL GEAR MOTOR

Identification (1.A.b)The bleed valve fuel gear motor consists of a positivedisplacement gear motor and end-of-stroke stopmechanism. It consists of two spur gears guided duringrotation by needle bearings.

Sealing at the drive gear shaft is provided by carbon seals.A secondary lip seal is mounted on the output shaft forfurther sealing.

Purpose (1.B.b)The fuel gear motor, which is driven by Pf, pressurecontrols the position of the bleed valves.

Location (2.A.b)The fuel gear motor is mounted to the aft end of the VBVstop mechanism.

Operation (2.C.b)The motor converts pressurized fuel into rotary shaft powerwhich is driven through the bleed valve stop mechanism tothe gear reduction stage of the bleed valve and masterballscrew actuator.

Fuel, which could leak past the different sealing provisions,is drained overboard through the starter air discharge ductfitting.


EFFECTIVITY


Page 51Oct 95ALL

OUTPUT SHAFT

O-RINGSEAL

VBV DRAINTUBE

BLEEDVALVE FUEL

GEAR MOTOR

VBV CLOSEDPORT TUBE

VBV OPENPORT TUBE

A

ATTACHINGPOINTS TO BLEED

VALVE STOPMECHANISM

A


PRIMARYSEAL

SECONDARYSEAL

DRIVE GEAR

SEE ASEE B

B A-A

A

VARIABLE BLEED VALVE FUEL GEAR MOTOR

75-32-00


EFFECTIVITY


Page 52Oct 95ALL

STOP MECHANISM

Identification (1.A.b)The stop mechanism consists of a housing, a hollowscrew, the main VBV flexible shaft, and a follower nut.

Purpose (1.B.b)The function of the bleed valve stop mechanism is to limitthe number of revolutions of the bleed valve fuel gearmotor to the number of revolutions required for acomplete cycle (opening-closing) of the VBV doors. Thislimiting function supplies the reference position forinstalling and adjusting the VBV actuators.

Location (2.A.b)The bleed valve stop mechanism is installed inside thefan frame midbox structure between the bleed valve fuelgear motor and the bleed valve and master ballscrewactuator at the 9:30 o'clock position.

Functional Description (3.D.b)The hollow screw is driven by the bleed valve fuel gearmotor. This hollow screw shaft holds the main VBVflexible shaft which connects the bleed valve fuel gearmotor to the master ballscrew actuator. The follower nuttranslates along the screw and stops the rotation of thebleed valve fuel gear motor when it reaches the ends ofthe screw threads.

The VBV feedback reverser arm is mounted on the bleed

75-32-00

valve stop mechanism housing. The feedback reverserarm links the feedback rod from the master ballscrewactuator to the feedback cable, which is routed to theMEC. Through this linkage, the MEC constantly monitorsthe angular position of the VBV doors.


EFFECTIVITY


Page 53Oct 95ALL

VARIABLE BLEED VALVE STOP MECHANISM


FORWARD

A

A

FOLLOWERNUT

PROTECTINGBOOT

OUTPUTSHAFT

MAINFLEX

SHAFTACME

SCREW

DOGSTOP

A

SEE A

SEE B

B A-A

75-32-00


EFFECTIVITY


Page 54Oct 95ALL

STOP MECHANISM

Functional DescriptionWith S/B 72-580 CFMI introduced a modification to theVBV stop mechanism.

The VBV kicker system modifies the VBV trackingschedule to further open the VBV doors (40° versus 25°)during transient operation. This positioning of the VBVdoors in association with other changes provides animprovement to hail and rain bypass from the primary.

The kicker system consists of a:- free lever- return lever- kicker stop

75-32-00737/Engines with S/B 72-580


EFFECTIVITY


Page 55Oct 95ALL

VBV KICKER SYSTEM

REVERSERARM

RETURNLEVER

CLEVISJAMNUT

KICKER STOP

NOTCH

FREE LEVER

VBV FEEDBACKCABLE

FEEDBACKROD

A

SEE A

FEEDBACKROD

INDEXHOLE

CLEVISPIN

WASHER

NUT

CLO

SE

BLEED VALVE ROTATEDFOR CLARITY

75-32-00737/Engines with S/B 72-580


EFFECTIVITY


Page 56Oct 95ALL

MASTER BLEED VALVE AND BALLSCREWACTUATOR

Identification (1.A.b)It consists of a speed reduction gearbox and a ballscrewactuator linked to a hinged door. Speed reduction isconsecutively carried out through one pair of spur gearsand then by two pairs of bevel gears. The last set ofbevel gears drives the ballscrew.

The ball bearing type screw and nut assembly consists ofa screw, nut, ball return tube, a clamp attached to twoscrews and washers, and 68 balls.

Purpose (1.B.b)The bleed valve and master ballscrew actuator transfersthe driving input from the bleed valve fuel gear motor tothe ballscrew actuator system.

Location (2.A.b)The master bleed valve and ballscrew actuator is locatedat the 11 o'clock position between the center hub and themidbox structure of the fan frame.

Functional Description (3.D.b)The ballscrew translating nut is held during rotation bytwo pins which slide within two slots in the actuator body.The travel of the nut is transmitted to the door by twolinks. The feedback rod is attached to the feedback leveron the bleed valve door. This permits the MEC to

75-32-00

constantly monitor the position of the bleed valve door.The output motion of the first pair of bevel gears istransferred to the other bleed valve and ballscrewactuators by the flexible shafts. The flexible shafts aredriven by the two ends of the output gear of this pair ofbevel gears.


EFFECTIVITY


Page 57Oct 95ALL

VARIABLE BLEED VALVE AND MASTER BALLSCREW ACTUATOR

A

SEE C

MAIN FLEXIBLESHAFT SOCKET

DOOR POSITIONFEEDBACK

LEVER

B

BALLSCREWACTUATOR

BALL

NUT

CLAMP

BALL RETURNTUBE

SCREW

FLEXIBLESHAFT

SOCKET

FLEXIBLESHAFT

SOCKET

TRANSLATINGNUT

FLEXIBLESHAFT

SOCKET

ATTACHINGBRACKET FOR VBVPOSITION SENSOR

(MONITORED)SEAL

INPUTSHAFT

SPEEDREDUCTIONGEARBOX

C

BALLSCREW

A

A

PROTECTINGBOOT

75-32-00


EFFECTIVITY


Page 58Oct 95ALL

BLEED VALVE AND BALLSCREW ACTUATOR

Identification (1.A.b)Each bleed valve and ballscrew actuator consists of abevel gear speed reduction gearbox and a ballscrew unitlinked to a hinged door.

Purpose (1.B.b)The bleed valve and ballscrew actuator transfers thedriving input from the master bleed valve and ballscrewactuator to the next ballscrew actuator.

Location (2.A.b)There are 11 bleed valve and ballscrew actuatorsconnected on either side of the master ballscrew actuator.

Functional Description (3.D.b)The translating nut is held during rotation by two pinswhich slide within two slots in the actuator body. The travelof this unit is transmitted to the door by two links. Thedriving gear of the speed reducer is used as a drive shaftto the other ballscrew actuators. A flexible shaft fits into ahex head drive in each end of the gear.

The ball bearing type screw and nut assembly consistsof a screw, nut, ball return tube, a clamp attached bytwo screws and washers, and 68 balls.

75-32-00


EFFECTIVITY


Page 59Oct 95ALL

VARIABLE BLEED VALVE AND BALLSCREW ACTUATOR

A

DOORHINGE

A-A

A

ATTACHINGBOLT TOENGINE

SHAFTSOCKET

A SHAFTSOCKET

DOOR

SEAL

B

BALL RETURNTUBE

SCREWCLAMP

NUT

BALL

C

BALLSCREWSHAFT

SOCKET

TRANSLATINGNUT

ATTACHINGBOLT

THRUSTBEARING

SEE C

ATTACHINGBOLT

SEAL

ANGLEGEARBOX

PROTECTINGBOOT

75-32-00


EFFECTIVITY


Page 60Oct 95ALL

BLEED VALVE AND BALLSCREW ACTUATOR

Functional DescriptionIntroduced in January of 1991, the 11 VBV doors weremodified with a series of scoops, slides and fairings.These items were added to direct ingested water, hailand sleet from the core flow path (primary) to the fanstream (secondary).

This VBV modification works in conjunction with anelliptical spinner, cutback splitter fairing and a new VBVschedule to provide an N1 flight idle speed of 32% versus45% when operating in hail and rain conditions.

75-32-00737/Engines with S/B 72-580


EFFECTIVITY


Page 61Oct 95ALL

SLIDE

SCOOP

FAIRING

VBV DOORTOUCHES

THE SCOOP

VARIABLE BLEED VALVE AND MASTER BALLSCREW ACTUATOR

75-32-00737/Engines with S/B 72-580


EFFECTIVITY


Page 62Oct 95ALL

VBV MAIN FLEXIBLE SHAFT

Identification (1.A.b)The main flexible shaft is an unshielded power corewhich has a hexagon fitting on one end and a splinedend fitting on the other. A spring is attached to thesplined end. The spring holds the shaft in position duringoperation and also permits easy removal of the shaft.

Purpose (1.B.b)The main flexible shaft transfers power from the fuelgear motor through the stop mechanism to the masterbleed valve and ballscrew actuator.

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EFFECTIVITY


Page 63Oct 95ALL

SHAFT

SPRING

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MAIN FLEXIBLE SHAFT


EFFECTIVITY


Page 64Oct 95ALL

VBV FLEXIBLE SHAFT

Identification (1.A.b)Each of the 11 shafts is an unshielded power corewhich has a hexagon fitting on one end and an eight-point fitting on the other end. A spring is attached tothe hexagon end. The spring holds the shaftassembly in position during operation and also permitseasy removal of the shaft assembly. The ferrules thatare installed in the struts of the engine fan frame aredesigned to support the flexible shaft assembliesduring operation.

Purpose (1.B.b)The flexible shaft transmits through its interconnection,rotational power to each of the 11 bleed valve andballscrew actuators.

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EFFECTIVITY


Page 65Oct 95ALL

FLEXIBLE SHAFT

SPRING

SHAFT

75-32-00


EFFECTIVITY


Page 66Oct 95ALL

VBV FEEDBACK CABLE

Identification (1.A.b)The VBV feedback cable is a flexible cable whichconnects the MEC VBV feedback system lever to theVBV actuation system at the master valve.

Purpose (1.B.b)VBV feedback cable movement transmits the position ofthe VBV's to the MEC.

Location (2.A.b)It's location starts at the connection to the stopmechanism bellcrank at 9 o'clock and is mounted downthrough the 6 o'clock tube bundle over to the MEC VSVlever arm at about the 8 o'clock position..

Operation (2.C.b)As the VBV hydraulic motor and drive system operate,the position signal is compared in the MEC through acomparative linkage system to the position commandestablished in the MEC through linkage with the VSVfeedback system. The VBV control valve discontinuesoperation of the hydraulic motor when the VBV feedbacksignal nulls the command input.

Functional Description (3.D.b)The VBV feedback system differs from the VSV feedbacksystem in that the feedback and command errormeasurement linkage system has a provision for

repositioning the feedback linkage null position asdirected by the VBV reset piston. This provides foractuation of the VBV's by other commands. Twocommands to the VBV reset piston may do this: acommand by the VBV reset valve when a rapiddeceleration change in VSV positioning is sensed by theVBV reset valve, or a command from the reverser signalvalve when the reverser is actuated.

Like the VSV feedback, it is important to accuratelyadjust (rig) the VBV feedback cable to the MEC to assureproper feedback inputs to the MEC. Also, like the VSVfeedback system, the VBV feedback cable is maintainedin tension during engine operation by a hydraulic loadcylinder in the control that is coupled to the VBVfeedback linkage. This tension load must be simulatedduring adjustment rigging of the feedback cable to theMEC.

75-32-00


EFFECTIVITY


Page 67Oct 95ALL

VBV FEEDBACK CABLE

FEEDBACK REVERSERARM CONNECTION

75-32-00

6 O'CLOCK STRUTBRACKET MOUNT

MECCONNECTION


EFFECTIVITY


Page 68Oct 95ALL

VBV SYSTEM OPERATION

Operation (2.C.b)The fuel gear motor is hydraulically activated bypressurized fuel. The MEC determines the direction andspeed of motor rotation. The gear motor drives the rotaryshaft which drives the gear reduction stage of the masterballscrew actuator through the stop mechanism. Theflexible shafts transmit power from the rotary shaft to theremaining ballscrew actuators.

Functional Description (3.D.b)The flexible shafts are supported by ferrules at theirmidpoints. The ballscrew actuators reduce shaft speedwith bevel-cut gears and convert rotary motion to linearoutput.

The actuator output is from a trunnion mount provided onthe translating ball nut. The mount is connected to thebleed valve by a tandem linkage to provide a rotationalmovement on the bleed valve pivotal axis. The directionof the bleed valve rotation is controlled by fuel gearmotor.

The fuel gear motor, actuated by the VBV control valve inthe MEC, drives the system to the command (open,closed or modulated) position with the required power.The VBV feedback mechanism relays the bleed valveposition to the MEC as the system approaches the

commanded position. The VBV control valve is movedtowards the null position (or minimum opening needed toneutralize the bleed valve loads) as the bleed valveapproaches the end of its stroke. This reduces motorspeed and allows the motor to engage the end-of-strokestops at low impact force.

75-32-00


EFFECTIVITY


Page 69Oct 95ALL

VBV SYSTEM AIRFLOW DIAGRAM


ACTUATOR

PRIMARY AIRFLOW

SECONDARY AIRFLOW

BLEED VALVEFUEL GEAR MOTOR


FAN OGVINNER

SHROUD

SPLITTERFAIRING

FAN OGV'S

75-32-00


EFFECTIVITY


Page 70Oct 95ALL


Functional DescriptionThe tracking schedule identifies the position required ofthe VBV's in percent of angle at a specified correctedcore engine speed.

The VBV kicker system is designed to improve CFM56-3operations in inclement weather (hail and rain)conditions. The purpose of the kicker is to modify theVBV schedule in order to fully open (40°) the VBV doorsduring transient operation and decel.

Efficient operation requires the bleed valves to be fullyclosed at or above 12,250 RPM corrected core speed. Asthe engine decelerates the VBV feedback rod will start tomove with the scheduled operation of the VBV masterbleed valve door. At the same time fuel pressure withinthe MEC will pull the feedback cable downwardmaintaining the free lever against the return lever.

75-32-00


EFFECTIVITY


Page 71Oct 95ALL

VBV TRACKING SCHEDULE

75-32-00

10,000 12,000 13,00011,000

N2R25 (RPM)

CFM56 -3 / - 3B / - 3C VBV TRACKING LIMITS

70006000 90008000

0%

20%

30%

40%

10%

- 10%

50%

60%

70%

80%

90%

100%

110%

OPEN

CLOSED

VBVPOSITION INPERCENT

9.51DEGREES

40DEGREES

Closed

VBV FEEDBACK ROD

REVERSER

ARM

RETURN

LEVER

FREE LEVER

NOTCH

KICKER STOP

VBV FEEDBACK

CABLE


EFFECTIVITY


Page 72Oct 95ALL


Functional DescriptionAs the engine decelerates the free lever stops movementof the feedback cable at 10° VBV opening by contactingthe kicker stop. When the free lever contacts the kickerstop on the fan frame, feedback cable movement ishalted. This is known as the deceleration switch point.


EFFECTIVITY


Page 73Oct 95ALL

KICKER DECELERATION SCHEDULE

10,000 12,000 13,00011,000

N2R25 (RPM)


70006000 90008000

0%

20%

30%

40%

10%

- 10%

50%

60%

70%

80%

90%

100%

110%

OPEN

CLOSED


9.51DEGREES

40DEGREES

Switch Point

VBV FEEDBACK ROD

REVERSER

ARM

RETURN

LEVER

NOTCH

KICKER STOP

VBV FEEDBACK

CABLE

FREE LEVER


EFFECTIVITY


Page 74Oct 95ALL


Functional DescriptionBased on this false feedback indication the MEC willcontinue to drive the VBV doors to a 40° full openposition.

At the lower speeds more booster air must be bled overinto the fan discharge to maintain an optimum flowthrough the core engine.

When the engine is accelerated the return lever willcontact the free lever at the acceleration switch point andprovide feedback to the MEC by the feedback cable.


EFFECTIVITY


Page 75Oct 95ALL

KICKER ACCELERATION SCHEDULE

10,000 12,000 13,00011,000

N2R25 (RPM)


70006000 90008000

0%

20%

30%

40%

10%

- 10%

50%

60%

70%

80%

90%

100%

110%

OPEN

CLOSED


9.51DEGREES

40DEGREES

VBV FEEDBACK ROD

REVERSER

ARM

RETURN

LEVER

FREE LEVER

VBV FEEDBACK

CABLE

KICKER STOP

NOTCH

Open


EFFECTIVITY


Page 76Oct 95ALL

5TH STAGE START BLEED VALVE

Identification (1.A.b)The 5th stage start bleed valve consists of a bleed valve,an air diffuser, an optional deflector baffle, andconnecting tubing to the start valve.

Purpose (1.B.b)The 5th stage start bleed system uses starter airpressure from the start valve to signal the bleed valve toopen and unload 4% of the compressor 5th stagepressure. This reduced pressure in the HPC sectionduring start will increase engine stall margin at lowstarting speeds. The start bleed system has nosignificant adverse effects on start time and EGT.

75-34-00


EFFECTIVITY


Page 77Oct 95ALL

5TH STAGE START BLEED SYSTEM COMPONENTS

FLANGE N

EGT WIRE HARNESS

FORWARD

HPC FLANGE P

AIR SIGNAL TUBE

AIR DIFFUSER

START BLEED VALVE

B

A

A

A

75-34-00

DEFLECTOR BAFFLE

SEE ASEE B

TO START VALVE


EFFECTIVITY


Page 78Oct 95ALL


Location (2.A.b)The 5th stage start bleed valve is located on the left sideof the HPC case at the 11 o'clock position.

75-34-00


EFFECTIVITY


Page 79Oct 95ALL

5TH STAGE START BLEED VALVE LOCATION AND INSTALLATION

AIR SIGNAL TUBE

AIR DIFFUSER

DEFLECTOR BAFFLE

FLANGE P

FLANGE N

INLET AIR TUBE

5TH STAGE STARTBLEED VALVE

BRACKET

BRACKET

AFT LOOKING FORWARD (ALF)

75-34-00


EFFECTIVITY


Page 80Oct 95ALL


Operation (2.C.b)

75-34-00

It is a pneumatically operated, normally closed valvewhich is opened when starter air pressure is applied tothe signal port. The air diffuser is attached to the exitport of the bleed valve to reduce the velocity of theexiting bleed air.


EFFECTIVITY


Page 81Oct 95ALL


AIR SIGNAL TUBEB-NUT

ELBOW

AIR DIFFUSER

INLET AIR TUBE

V-BAND CLAMP

O-RINGGROOVE

JAM NUTO-RING

METALGASKET

SIGNAL PORT

V-BAND CLAMP

5TH STAGEBLEED AIR

5TH STAGESTART BLEED

VALVE

AIR OUTLET PORTAIR INLET PORT

METALGASKET

B

75-34-00


EFFECTIVITY


Page 82Oct 95ALL


Functional Description (3.D.b)During engine start, air pressure is ducted to the startvalve and the starter is engaged (start valve open). Afterstart valve opening, air pressure is applied to a pressuresensing port just downstream of the valve which directsair to the signal port on the start bleed valve, causing it toopen. This allows engine core airflow to exit the HPC forimproved stability. Bleed air passes through the valve,then the diffuser, and is deflected against an optionalbaffle where it mixes with engine compartment air. Theair discharges overboard through the gap between theaft end of the fan duct cowl and the exhaust sleeve.

When the starter is disengaged, the start valve closes,cutting off the air signal to the bleed valve. Springpressure aided by a 5th stage pressure boost travelingthrough a small orifice to the spring side of the pistonsleeve closes the bleed valve and holds it shut duringnormal engine operation. This pressure boost assist willhold the valve shut in the case of a spring (or valve)failure.

75-34-00


EFFECTIVITY


Page 83Oct 95ALL


STARTER

START VALVE AIRSIGNALTUBE

SPRINGPISTON

VALVEBODY

EXITPORT

DISCHARGEINTO CORE

CAVITY

STARTERAIR

PRESSURESIGNAL

5TH STAGEAIR

5TH STAGEPRESSURE

BOOST

VALVE SHOWN CLOSED

B

FORWARD

75-34-00


EFFECTIVITY


Page 84Oct 95ALL


75-00-00


EFFECTIVITY



ENGINE INDICATING SYSTEMObjectives:At the completion of this section a student should be able to:.... identify the components comprising the indicating system of the CFM56-3/3B/3C engine (1.A.x).....state the purpose of the indicating system of the CFM56-3/3B/3C engine (1.B.x).....state the purpose of the components comprising the indicating system of the CFM56-3/3B/3C engine (1.B.x)..... locate the components comprising the indicating system of the CFM56-3/3B/3C engine (2.A.x)..... identify the aircraft interfaces associated with the indicating system of the CFM56-3/3B/3C engine (2.B.x).....describe the component operation of the indicating system of the CFM56-3/3B/3C engine (2.C.x).....describe the particular component functions of the indicating system of the CFM56-3/3B/3C engine (3.D.x).


EFFECTIVITY


Page 2Oct 95ALL

ENGINE INDICATING SYSTEM

Identification (1.A.a)It consists of the engine tachometer system, whichmeasures rotational speed of the low speed rotor (N1)and high speed rotor (N2), the engine EGT indicatingsystem and Airborne Vibration Monitoring (AVM) system.

Purpose (1.B.a)The indicating system (77-00-00) is to verify proper andsafe engine operation throughout the flight envelope.

77-00-00


EFFECTIVITY


Page 3Oct 95ALL

ENGINE VIBRATION INDICATION- INDICATES ENGINE VIBRATIONLEVEL IN THE FAN SECTION OR

HPC, WHICHEVER IS HIGHER

N1 RPM INDICATION -INDICATES LP ROTOR

SPEED IN % RPM

ENGINE INDICATING SYSTEM

77-00-00

EGT INDICATION -INDICATES TURBINE

EXHAUST GASTEMPERATURE IN °C

N2 RPM INDICATION -INDICATES HP ROTOR

SPEED IN % RPM


EFFECTIVITY



N1 SPEED SENSOR

Identification (1.A.b)The sensor consists of a rigid metal tube with a mountingflange and two-connector receptacle. Within the tube isan elastomer damper and a magnetic head sensor withtwo protruding pole pieces.

Purpose (1.B.b)The N1 speed sensor is a pulse counter that senses N1

rotor speed and provides signals to the N1 tachometerindicator and PMC.

Location (2.A.b)The N1 speed sensor is mounted in strut No. 5 of the fanframe at the 4 o'clock position and is secured to the fanframe with two bolts. When the N1 speed sensor isinstalled on the engine, only the two-connectorreceptacle and the body are visible.

Operation (2.C.b)Actual N1 fan speed is measured by speed sensorelements which provide an AC voltage whose frequencyis proportional to the fan speed.

Functional Description (3.D.b)The sensor incorporates dual sensing elements with oneelement providing N1 signal for the PMC and the otherelement providing signal to the N1 tachometer indicator.A magnetic ring mounted on the fan shaft is provided

with teeth. The passage of each tooth generates analternating voltage in the sensor element proportional toactual N1 speed.

Note: The sensor ring has one tooth thicker than the29 others to generate a signal of greater amplitude usedas phase reference for trim balance.


EFFECTIVITY



PULSEGENERATING

ROTOR

FANSHAFT

NO. 2 BEARING

SENSORPROBE

A

B

RECEPTACLE BODY A

A

SENSORPROBE

MOUNTINGFLANGE

ELASTOMERDAMPER

POLEPIECES

SEED

B

B

DC

SEE C


A-A B-B

N1 SPEEDSENSOR

SEE B

SEE A

N1 SPEED SENSOR


EFFECTIVITY


Page 6Oct 95ALL

EGT INDICATING SYSTEM

Identification (1.A.b)EGT is measured by nine thermocouple probes. Thesignals transmitted by these probes are routed throughrigid thermocouple harnesses and one of three extensionleads which make up the EGT thermocouple harnessassembly.

There are two identical and interchangeable left-handthermocouple harness segments which consist of:

- A flange-mounted secondary junction box with areceptacle connector for connection with the mainjunction box extension lead.

- Three rigid metal tubes, each of them provided witha flange-mounted chromel-alumel thermocoupleprobe, that are permanently mounted to thesecondary junction box.

The right-hand thermocouple harness segment consistsof:

- A flange-mounted secondary junction box with areceptacle connector for connection with right-handharness segment extension lead.

- Three rigid metal tubes, each of them provided witha flange-mounted chromel-alumel thermocoupleprobe, that are permanently mounted to thesecondary junction box.

77-21-00

The main junction box and leads assembly consists of:- A main junction box with two receptacle connectors

for connecting with the right-hand harness segmentextension lead and the forward extension lead.

- Two main junction box extension leads which arerigid metal tubes, each permanently affixed to themain junction box on one end with a mobileconnector on the other end for connection to theleft-hand secondary junction boxes.

The right-hand harness segment extension lead is a rigidmetal tube fitted with a mobile connector at each end.One for connection with the right-hand secondaryjunction box and the other for connection with the mainjunction box.

The forward extension lead is a rigid metal tube with amobile connector at one end for connection with the mainjunction box and either a terminal block or a receptacleconnector on the other end for airplane interface. Thelead provides ease of access for engine removal andEGT system testing.


EFFECTIVITY



EGT THERMOCOUPLE HARNESS AND NINE PROBES

LOWER EGTHARNESS

PROBE NO. 3

PROBE NO. 4

PROBE NO. 2

PROBE NO. 1

PROBE NO. 5

SEE A

PROBE NO. 8

PROBE NO. 7

PROBE NO. 6

RIGHTJUNCTION

BOX

PROBE NO. 9

RIGHT EGTHARNESS

LEFT EGTHARNESS

FORWARDEXTENSION CABLE

LOWERJUNCTION

BOX

A

INTERFACETERMINAL

RIGHT HARNESSEXTENSION LEAD

LEFTJUNCTION

BOX

LOWERHARNESS

EXTENSION

MAINJUNCTION

BOX

77-21-00


EFFECTIVITY


Page 8Oct 95ALL

EGT INDICATING SYSTEM

Purpose (1.B.b)The Exhaust Gas Temperature (EGT) indicating systemprovides a visual indication in the flight compartment ofan averaged exhaust gas temperature as it passesthrough the LPT of each engine.

Location (2.A.b)The thermocouple probes are installed in the stage 2LPTN assembly.

Operation (2.C.b)The thermocouple probes create a voltage that isproportional to the temperature around the chromel-alumel hot-junction. Parallel chromel-alumel leadsconnect the probes to the junction boxes. The junctionboxes transfer an average of the voltages for delivery tothe flight deck indicator.

77-21-00


EFFECTIVITY


Page 9Oct 95ALL

GAS INLET

A-A

FORWARD

CHROMEL-ALUMELTHERMOCOUPLE TIP

SPHERICAL JOINTCONDUIT

GAS FLOW EXHAUSTOUTSIDE LPT CASE

A

A

MOUNTINGFLANGE

LPT CASE

GAS EXHAUST

THERMOCOUPLETIP

DUCT

MOUNTFLANGE

STAGE 2NOZZLE VANE

CALIBRATEDGAS FLOW

(P4.95)(FOUR HOLES)

EGT THERMOCOUPLE

77-21-00


EFFECTIVITY


Page 10Oct 95ALL

AIRCRAFT VIBRATION SENSING SYSTEM

Identification (1.A.b)The system consists of two accelerometers (vibrationsensors), a vibration indicator for each engine, and asignal conditioner.

Purpose (1.B.b)Abnormal engine vibration, sudden or progressive, is apositive indication of an engine malfunction. Abnormalvibration can be caused by compressor or turbine bladedamage, rotor imbalances, or other problems. Earlywarning of engine malfunction permits corrective actionbefore extensive damage results.

The aircraft vibration sensing system continuously showsengine vibration levels.

Operation (2.C.b)With engine operating, the engine accelerometersgenerate signals proportional to engine motion in a radialdirection. These signals are received by the signalconditioner, where they are amplified to signal levelssuitable for flight deck indicator operation. The strongestsignal is then sent to the flight deck vibration indicator foreach engine.

77-31-00


EFFECTIVITY


Page 11Oct 95ALL

NO. 1 BEARINGVIBRATION

SENSOROR

FFCCV(ALTERNATE)

SENSOR

TRF (CORE)SENSOR

ENGINE 1

ENGINE 2

SAME ASENGINE 1

VIBRATIONSIGNAL

CONDITIONER

AIRCRAFT VIBRATION SENSING SYSTEM

0

1 5

23

4

0

1 5

23

4VIBRATION

VIBRATION


EFFECTIVITY


Page 12Oct 95ALL

NO. 1 BEARING VIBRATION SENSOR

Identification (1.A.b)The No. 1 bearing (NOB) vibration (fan) sensor has acharge sensitivity of 100 pc/g.

Purpose (1.B.b)This sensor senses both low (no. 1 bearing) and high(no. 3 bearing) speed rotor vibration levels.

Location (2.A.b)The No. 1 bearing (NOB) vibration (fan) sensor ismounted on the No. 1 bearing housing at the 9 o'clockposition. The lead connector is on the fan frame midboxstructure aft frame at the 3 o'clock position.


EFFECTIVITY


Page 13Oct 95ALL

NO. 1 BEARING VIBRATION SENSOR

NOB VIBRATION(FAN) SENSOR

(9 O'CLOCK)

CONNECTOR

SHOCKABSORBERS

SENSITIVEAXIS

CABLE

CLAMPS

VIBRATIONSENSOR

(ACCELEROMETER)

77-31-00


EFFECTIVITY


Page 14Oct 95ALL

FFCCV SENSOR (ALTERANATE SENSOR)

Identification (1.A.b)The FFCCV or Fan Frame Compressor Case Verticalsensor has a charge sensitivity of 100 pc/g.

Purpose (1.B.b)This sensor is an alternate to the No.1 bearing sensorand senses both low (no. 1 bearing) and high (no. 3bearing) speed rotor vibration levels.

Location (2.A.b)The FFCCV or Fan Frame Compressor Case Verticalsensor is mounted just below the No. 1 bearing sensorlead connection on the fan frame midbox structure at the3 o'clock position.


EFFECTIVITY


Page 15Oct 95ALL

FAN FRAME COMPRESSOR CASE VERTICAL (ALTERNATE) SENSOR

A

A


EFFECTIVITY


Page 16Oct 95ALL

CORE VIBRATION SENSOR

Identification (1.A.b)The core vibration sensor has a charge sensitivity of 50pc/g. Older CFM56-3 engine systems may have a corevibration sensor with a charge sensitivity of 20 pc/g.

Check appropriate part numbers to verify sensitivity.

Purpose (1.B.b)This sensor senses both low (no. 5 bearing) and high(no. 4 bearing) speed rotor vibration levels.

Location (2.A.b)The core vibration sensor is mounted on the forwardflange of the turbine frame at about the 12 o'clockposition. The lead connector is mounted with a bracket tothe forward high pressure compressor case flange "N" atthe 5 o'clock position.

77-31-00


EFFECTIVITY


Page 17Oct 95ALL

CORE VIBRATION SENSOR

A

SEE A

77-31-00


EFFECTIVITY


Page 18Oct 95ALL


77-00-00


EFFECTIVITY



OIL SYSTEMObjectives:At the completion of this section a student should be able to:.... identify the components comprising the oil system of the CFM56-3/3B/3C engine (1.A.x).....state the purpose of the oil system of the CFM56-3/3B/3C engine (1.B.x).....state the purpose of the components comprising the oil system of the CFM56-3/3B/3C engine (1.B.x).....describe the flow sequence of the oil system for the CFM56-3/3B/3C engine (1.D.x)..... locate the components comprising the oil system of the CFM56-3/3B/3C engine (2.A.x)..... identify the aircraft interfaces associated with the oil system of the CFM56-3/3B/3C engine (2.B.x).....describe the component operation of the oil system of the CFM56-3/3B/3C engine (2.C.x).....describe routine servicing of the oil system of the CFM56-3/3B/3C engine (2.D.x).....describe the particular component functions of the oil system of the CFM56-3/3B/3C engine (3.D.x).


EFFECTIVITY


Page 2Oct 95ALL

INTRODUCTION

Purpose (1.B.b)The engine oil system is a self-contained, center-vented,recirculating type system. Each engine has an independentoil system comprised of oil storage, distribution, andindicating to provide lubrication and cooling for the enginemain bearings, radial drive shaft bearings, and gears andbearings in the TGB and AGB.

79-00-00


EFFECTIVITY


Page 3Oct 95ALL

COMPLETE OIL SYSTEM

OIL SUPPLY OIL SCAVENGE

OIL TANK

AGB

TGB

FORWARDSUMP

AFTSUMP

79-00-00

- 3 MAGNETIC PLUG + SCREENS- 3 SCAVENGE PUMPS- 1 COMMON SCAVENGE FILTER- 2 HEAT EXCHANGERS

- 1 PRESSURE PUMP- 1 PRESSURE FILTER

SUPPLY CIRCUIT

SCAVENGE CIRCUIT

VENTING SYSTEM


EFFECTIVITY


Page 4Oct 95ALL

INTRODUCTION

Flow Sequence (1.D.b)The oil tank provides storage of oil for continuousdistribution by the supply system. Oil flows from the tankto the supply pump in the lubrication unit on the AGB.

The four positive displacement oil pumps are on a singleshaft driven by the AGB. The supply pump incorporatesa pressure relief valve that diverts the oil flow to ascavenge pump in the event of abnormal operatingconditions. The pressure relief valve opens when thepressure downstream of the supply pump exceeds 305psi (2,100 kPa).

During normal operating conditions, the oil flows throughthe oil supply filter prior to distribution. When the supplyfilter becomes clogged, the flow will divert through thebypass valve. The bypass valve starts to open when thepressure drop reaches 17.4-20.3 psi (120-140 kPa)across the oil supply filter.

The clogging indicator pops up before a filter bypasscondition. When the pressure drop across the supplyfilter reaches 11.6-14.5 psi (80-100 kPa), the magnetsare forced apart - the indicator pops up, becoming visiblein the glass inspection bowl. A bimetal spring preventsactuation at low operating temperatures.

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EFFECTIVITY


Page 5Oct 95ALL

OIL SUPPLY SYSTEM SCHEMATIC

ANTI-SIPHON

OIL TANK

FORWARDSUMP

AFTSUMP

OILPRESSURE

SENSOR

OILPRESSURE

SWITCH

CLOGGINGINDICATOR

AGB

TGB

PRESSURE PUMP

LUBE UNIT

PRESSURE RELIEFVALVE

PRESSUREFILTER

BYPASSVALVE

CHECK VALVE

TO AGB SCAVENGEPUMP SUCTION

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EFFECTIVITY


Page 6Oct 95ALL

INTRODUCTION

Flow SequenceAfter distribution, oil is returned to the lubrication unitfrom three sumps. The forward sump services the No. 1,No. 2 and No. 3 main bearings. The aft sump servicesthe No. 4 and No. 5 main bearings. The gearbox sumpfor the AGB also collects oil through an external tubefrom the TGB.

The lubrication unit contains a scavenge pump for eachsump. The oil is drawn through one of three MagneticChip Detectors (MCD's). Oil upon leaving the MCD'sreturns through the common scavenge filter assembly.When the filter becomes clogged, the flow will divertthrough the bypass valve. Before a filter bypasscondition occurs, a flight deck indication of scavengefilter clogging will light at 25-27 psi (172.2-186 kPa).When the pressure drop across the scavenge filterreaches 28-34 psi (193-234 kPa), the filter cloggingindicator pops up becoming visible in the glass bowl. Abimetal spring prevents clogging indicator actuation atlow operating temperatures. The bypass valve starts toopen when the pressure drop reaches 36.3-39.2 psi(250-270 kPa) across the scavenge filter. Beforereturning to the engine oil tank, the oil is cooled in themain oil/fuel heat exchanger. Fuel enters the cylindricalcore through the fuel inlet in the housing. It flows thelength of the core through half the core tubes. The fuelflows around a baffle in the core access cover and

returns through the remaining core tubes.

Oil passes through the servo fuel heater and enters themain oil/fuel heat exchanger perpendicular to the fuelflow. The oil circulates around the fuel tubes in the core,transferring heat to the fuel by convection and condition.The cooled oil exists back through the servo fuel heaterand is returned to the oil tank.

A drain is provided at the forward and aft bearingcompartment for possible oil leaking past the stationaryair/oil seal. The forward seal drain exits through the8 o'clock fan frame strut. The aft seal drain exits throughthe 6 o'clock turbine frame strut.

The bearing sumps and gearboxes are interconnected tocollect oil vapors before air/oil separation and venting.The oil tank vent and the TGB/AGB sump are connectedto the forward sump. Vapors from the forward and aftsumps pass through rotating air/oil separators into themain shaft center vent tube to be vented out the exhaust.The separated oil is returned to the sumps.

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EFFECTIVITY


Page 7Oct 95ALL

OIL SCAVENGE AND VENT SYSTEM SCHEMATIC

FORWARDSUMP

CENTERVENTTUBE

VENT THROUGHDRIVE SHAFT

HOUSING

OILTANK

MAINOIL/FUEL HEAT

EXCHANGER

LUBRICATION UNIT1

CLOGGINGINDICATOR

CHECKVALVE

SCAVENGEFILTER

SERVOFUEL

HEATER

FROMPRESSURE

RELIEFVALVE

1 ACTUAL SCAVENGE FEEDS AREINTO BOTTOM OF LUBRICATION UNIT

HEATEXCHANGEROIL BYPASS

VALVE

BYPASS VALVEÐP = 36.3 - 39.2 PSI

(250 - 270 kPa)

MCD'S(THREE PLACES)

SCAVENGEPUMPS

(THREE PLACES)

AFTSUMP

AGB TGB

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EFFECTIVITY


Page 8Oct 95ALL

OIL TANK

Identification (1.A.b)The oil tank is a fabricated light alloy weldment envelopewith a sealed cast light alloy cover. It has an externalflame-resistant coating and five inner bulkheads toreduce sloshing and strengthen the tank. A sight glass isprovided on the outboard side of the tank to check oillevel and a magnetic drain plug is located at the bottomof the tank.

Total volume (usable oil plus residual oil plus air) of theoil tank is 5.3 U.S. gallons (20 liters). It has an oilcapacity (usable oil plus residual oil) of 4.8 U.S. gallons(18 liters). Engine No. 1 oil tank has 2% less capacityand engine No. 2 oil tank has 3% more capacity due towing inclination angle.

Several operational components are incorporated intothe tank cover:

- The filler cap with scupper, scupper drain andscreen.

- Lube supply port, suction tube and screen.

- Lube scavenge port, located next to the lubesupply port.

- Air vent outlet to the forward sump.

- Anti-siphon device and tube.

- Air/oil separator and tube.

- Oil quantity transmitter mounting boss.

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EFFECTIVITY


Page 9Oct 95ALL

OIL TANK COMPONENT IDENTIFICATION

FILLER CAP

OIL QUANTITYTRANSMITTER

SCUPPER

SIGHT GLASS

FORWARD

LUBESUPPLY

TUBE

VENT TUBEANTI-SIPHON

TUBE

LUBESCAVENGE

TUBE

SCUPPERDRAINTUBE

OILTANK

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EFFECTIVITY


Page 10Oct 95ALL

OIL TANK

Purpose (1.B.b)The engine oil tank is part of oil storage and provides acontinuous supply of oil for distribution.

Location (2.A.b)It is located on the lower right side of the fan case.

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EFFECTIVITY


Page 11Oct 95ALL

OIL TANK LOCATION

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AGB

OIL TANKLUBRICATIONUNIT

SCAVENGE FILTER


EFFECTIVITY


Page 12Oct 95ALL

OIL TANK FILLER CAP

Identification (1.A.b)The oil tank filler cap consists of a locking assemblyfastened to the filler cap body by chain, a sampling tube,a strainer and a check valve incorporated in the filler capbody.

- The locking plug assembly consists of a piston,spring, washers, ball and plug. With the lockinghandle lowered, the ball compresses the springwhich exerts a force on the seal against the body.

- The check valve consists of a diaphragm whichseals the lower filler cap body using oil tankpressure. The check valve ensures that no oilleakage occurs while the oil tank is pressurized,even if the locking plug is incorrectly installed.

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EFFECTIVITY


Page 13Oct 95ALL

OIL TANK FILLER CAP

A

A

LOCKINGPLUG

ASSEMBLY

LOCKINGHANDLE

SEAL

STRAINER

FLEXIBLEDIAPHRAGM

CHAIN

BALL

SAMPLINGTUBE

PISTON

BODY

PLUG

SPRING

A-A

A

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SEEA


EFFECTIVITY


Page 14Oct 95ALL

OIL TANK AIR/OIL SEPARATOR

Purpose (1.B.b)The air/oil separator reduces the amount of air trappedwithin the returning oil flow to the oil tank.

Operation (2.C.b)Oil is drawn from the bottom of the oil tank through asuction tube attached to the tank cover. Returning oildischarges tangentially into the air/oil separator wherethe air is spun out through the air vent to the forward oilsump.

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EFFECTIVITY


Page 15Oct 95ALL

OIL TANK AIR/OIL SEPARATOR

PRESSUREBALANCE PORT DEAERATOR

ASSEMBLY

OIL-INFROM HEAT

EXCHANGERS

TANK COVER

TANK COVER

OIL-IN ORIFICE

RETURN TUBE

OIL RETURNCAVITY

TOFORWARD SUMP

SWIRLER

DEFLECTOROILAIR

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EFFECTIVITY


Page 16Oct 95ALL

OIL TANK ANTI-SIPHON

Purpose (1.B.b)The anti-siphon device prevents the oil from beingsiphoned through the oil supply when the engine is notoperating.

Operation (2.C.b)After engine shutdown, the oil pressure downstream ofthe supply pump falls below the oil tank internal pressure.This enables the lubrication unit to be unprimed by air inthe oil tank. The oil is forced back into the oil tankthrough the anti-siphon tube.

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EFFECTIVITY


Page 17Oct 95ALL

OIL TANK ANTI-SIPHON DEVICE

BRACKET

TANK COVER

OIL-OUT TUBE

TANK COVER

OIL-OUT TUBE

SCREEN

INTERNALDUCT (A)

OILSUCTION

ENGINESHUTDOWN

AIR

NORMALOPERATION

OIL BYPASS IN AFT SUMPLUBRICATION SYSTEM

TO PRESSUREPUMP

AFT SUMP OILPRESSURE SUPPLY

INTERNALDUCT (B)

OIL-OUT ELBOW TOPRESSURE PUMP

OIL-OUT TOPRESSURE

PUMP

ANTI-SIPHONOIL SUPPLY

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EFFECTIVITY


Page 18Oct 95ALL

OIL DISTRIBUTION

Identification (1.A.b)The oil distribution system consists of the followingcomponents:

- Lubrication unit

- MCD's (part of Lubrication Unit)

- Supply filter (part of Lubrication Unit)

- Scavenge filter

- Monitoring indicators

- Main fuel/oil heat exchangers

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EFFECTIVITY


Page 19Oct 95ALL

OIL DISTRIBUTION SYSTEM COMPONENT LOCATION

AGB

FUEL PUMP

SCAVENGEFILTER LUBRICATION

UNITFORWARD

TGB

SERVO FUELHEATER

MEC

SEE A

MAIN OIL/FUELHEAT

EXCHANGER

A

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EFFECTIVITY


Page 20Oct 95ALL

LUBRICATION UNIT

Identification (1.A.b)The lubrication unit contains the following:

- Four positive displacement pumps (three scavengepumps and the supply pump)

- Oil supply filter, check valve and bypass valve withclogging indicator

- Pressure relief valve located on the oil supply pumpdischarge side of the unit

- Three Magnetic Chip Detectors (MCD's)

Location (2.A.b)The lubrication unit is located on the AGB near thebottom of the fan case on the left side.

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EFFECTIVITY


Page 21Oct 95ALL

OIL SYSTEM COMPONENTS - LUBRICATION UNIT

SCAVENGE PUMP

CHIP DETECTORS(MAGNETIC PLUG

AND SCREEN)

ANTI-CLOGGINGVALVE

CHECK VALVE

PRESSURE FILTER

RELIEF VALVE

PRESSURE PUMP

SCAVENGE OIL FROM:

FROMOIL TANK

SCAVENGE FILTERTO HEAT EXCHANGERS

AGBFORWARD

SUMPAFT

SUMP

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EFFECTIVITY


Page 22Oct 95ALL

MAGNETIC CHIP DETECTORS

Identification (1.A.b)Three MCD's are used on the lubrication unit, one on theinlet of each scavenge pump. Each has a removablemagnetic plug and a scavenge screen.

Purpose (1.B.b)There purpose is to trap ferrous/nonferrous particulatesbefore entering the lubrication unit.

Location (2.A.b)The MCD's are located at the inlet to the scavengepumps.

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EFFECTIVITY


Page 23Oct 95ALL

MAGNETIC CHIP DETECTOR ASSEMBLY

AGB/TGB

FWD. SUMP

AFT SUMP

CHIPDETECTORASSEMBLY

AGB

MAGNET

PLUGASSEMBLY

PIN

SCAVENGESCREEN

SLEEVE

SPRING

SEALINGSPOOL

PLUG ASSEMBLY REMOVED(PLUG CAVITY SEALED OFF)

OIL-INOIL-OUT

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EFFECTIVITY


Page 24Oct 95ALL

OIL SUPPLY FILTER

Identification (1.A.b)The filter is a 44 micron cleanable element. Theassembly contains a pressure relief valve and a bypassvalve with visual clogging indicator.

Purpose (1.B.b)To screen particle contamination contained within the oilsupplied from the oil tank.

Location (2.A.b)The oil supply filter is housed in the lubrication unit.

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EFFECTIVITY


Page 25Oct 95ALL

LUBRICATION UNIT - OIL PRESSURE FILTER ASSEMBLY

CHECKVALVE

PRESSUREPUMP

PRESSURERELIEFVALVE

FILTERDRAINPLUG

FILTERCARTRIDGE

FILTERCARTRIDGE

CLOGGINGINDICATOR

PRESSURERELIEF VALVE

FILTERCOVER

CLOGGINGINDICATOR

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EFFECTIVITY


Page 26Oct 95ALL

OIL SCAVENGE FILTER

Identification (1.A.b)The scavenge filter assembly consists of a replaceablefilter cartridge, a bypass valve with visual cloggingindicator and a non-return valve.

Purpose (1.B.b)To screen particle contamination contained within the oilscavenged from the engine sumps.

Location (2.A.b)The scavenge oil filter is installed in series between thescavenge pump outlet and the main oil/fuel heatexchanger. The assembly is located just above thelubrication unit.

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EFFECTIVITY


Page 27Oct 95ALL

OIL SYSTEM COMPONENTS - COMMON SCAVENGE FILTER ASSEMBLY

OIL-IN

PRESSURE TAPPINGS FORFLIGHT DECK INDICATOR

SCAVENGE OILTEMPERATURE TAP

OIL-OUT TOHEAT EXCHANGERS

FILTER REMOVAL

FILTER CARTRIDGE

CLOGGINGINDICATOR

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EFFECTIVITY



MAIN OIL/FUEL HEAT EXCHANGER

Identification (1.A.b)The main oil/fuel heat exchanger is of a tubular typeconstruction and consists of the housing, removable coreand core access cover.

Both fuel and oil portions of the oil/fuel heat exchangercontain bypass valves. This permits fuel and/or oil tobypass the core in the event of a blockage. A drain portis also provided to check for possible fuel leaks from thecore ends into the core housing.

Purpose (1.B.b)The main oil/fuel heat exchanger is designed to reducethe temperature of the scavenge oil prior to returning tothe oil tank.

Location (2.A.b)The main oil/fuel heat exchanger is located at the 9o'clock position on the fan case and is attached to thefuel pump and the servo fuel heater.


EFFECTIVITY




FUEL DRAIN TUBE

FUEL PUMP

CORE ACCESSCOVER

OIL-OUT TUBE

OIL-IN TUBE

SERVO FUEL HEATER



EFFECTIVITY




Operation (2.C.b)Oil received from the servo fuel heater passes externallyover the core tubes of the main oil/fuel heat exchanger.Heat from the oil is transferred through the process ofconvection to the fuel passing through the tubes from thelow pressure stage of the fuel pump. The cooled oil isthen sent back to storage in the engine oil tank. Theheated fuel returns to the fuel pump and is processedthrough the main fuel filter. In the event of a blockagethe fuel bypass will open at approximately 26 psid, andthe oil bypass at approximately 130 psid.


EFFECTIVITY




OIL-OUT TOOIL TANK

HOUSING

END COVER

OIL-IN TOBYPASS VALVECORE

DRAIN PORT

ATTACHINGFLANGE TOFUEL PUMP

FUEL-IN FUEL-OUT

OIL-INTO CORE

A

A

FUEL-OUT

FUEL BYPASSVALVE

SERVO FUELHEATER

ATTACHINGFLANGE

A-A B-B

B

OIL BYPASS VALVE

B

FUEL-IN


EFFECTIVITY



OIL SYSTEM MONITORING

Identification (1.A.b)To properly monitor the oil system, the followingindications are available:

- Oil pressure: Reads differential pressure betweenforward sump supply and TGB vent pressure.

- Oil temperature: Reads scavenge oil temperatureat the scavenge filter.

- Oil quantity: Reads quantity (flight deck) from oiltank transmitter. System also provides for a tankvisual indication.

- Filter clogging (scavenge): Senses scavenge filterdifferential pressure.

- Low oil pressure: Senses differential pressurebetween forward sump supply and TGB ventpressure.

Purpose (1.B.b)Indicating systems provide measurements of oil quantity, oilpressure and oil temperature. Warning lights also provide alow oil pressure warning and oil filter bypass warning. Thecondition of the engine oil system and the performance ofassociated engine components are determined by visualindication of these systems in the flight compartment.


EFFECTIVITY



OIL SYSTEM MONITORING

AGB

SCAVENGEFILTER

LUBRICATIONUNIT

OIL TANK

OILPRESS.

OILFILTER

DARK COLOR

NO SERVICING REQUIRED

VISUAL OIL LEVEL

LIGHT COLOR

ADD OIL

MAIN OIL/FUEL HEATEXCHANGER


EFFECTIVITY



VISUAL CLOGGING INDICATORS

Purpose (1.B.b)The visual clogging indicators provide a visual indicationof impending filter bypass.

Location (2.A.b)The oil supply filter and the oil scavenge filter are bothequipped with visual clogging indicators.


EFFECTIVITY



CLOGGED FILTER(POPPED OUT)

UPSTREAMPRESSURE

BYPASS

HYDRAULICPISTON

FILTERUPSTREAMPRESSURE

ARMEDPLUNGER

INSPECTIONCUP

TRIPPEDPLUNGER

CLOGGINGINDICATOR

CLOGGING INDICATORS CROSS SECTION

NORMAL(RESET)


EFFECTIVITY


Page 36Oct 95ALL

OIL SYSTEM SERVICING

Description (2.D.b)This section contains information for filling of oil,changing of oil, and flushing the engines oil system.

When servicing the oil system apply the generalguidelines shown below.

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EFFECTIVITY



OIL SERVICING GUIDELINES

FLUSH THE OIL SYSTEM IF FUMES INDICATE A MIXTURE OF FUEL AND OILOR SYSTEM IS CONTAMINATED

OIL CAN BE CHANGED THROUGH SERVICING

DO NOT MIX TYPE 1 AND TYPE 2 OILS

DRAIN AND FLUSH SYSTEM IF CHANGING FROM TYPE 1 TO TYPE 2 OIL

DO NOT SERVICE WITH UNAPPROVED BRANDS

WAIT AT LEAST 5 BUT NO MORE THAN 30 MINUTES BEFORE SERVICING


EFFECTIVITY


Page 38Oct 95ALL


DescriptionAfter open the oil tank access door do a check of the oilquantity sight gage. The sight gage for the oil tankshows a bright view when the oil level falls below thegage. It shows a black view when the oil level is higherthan the gage. The indication of a black view shows thata sufficient quantity of oil is in the tank for airplanedispatch. A sufficient quantity is more than 2.5 U.S.gallons (9.5 liters), or more than 60% full, as shown onthe pilots' center instrument panel.

If the indication of a bright view is showing through thesight gage then the oil tank requires servicing. The sightgage does not give an indication that the oil tank is full orempty.

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EFFECTIVITY



OIL SIGHT GLASS LEVEL INDICATION

BRIGHT IMAGE BLACK IMAGE

SUFFICIENT OIL LEVELINSUFFICIENT OIL LEVEL

OIL TANKOIL TANK

SIGHT GLASS SIGHT GLASS

REFLECTED LIGHT

15o 15o

INCIDENT LIGHT

VIEW PORT VIEW PORT


EFFECTIVITY


Page 40Oct 95ALL


DescriptionFilling of the oil tank can be accomplished by one of twoprocedures:

- gravity fill method

- remote fill method.

When you gravity fill the oil tank add oil to the fill port andstop just before the oil level reaches the overflow port.

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EFFECTIVITY


Page 41Oct 95ALL

OIL TANK SERVICING (GRAVITY FILL METHOD)

12-13-11

FILLER CAPHANDLE IN THEOPEN POSITION

FILLER CAPHANDLE IN THE

CLOSED POSITION

LOCKING PINS TOTHE FILLER CAP

ARE NOT ENGAGED

OVERFLOWPORT

SCUPPER

LOCKING PINS3 POSITIONS


EFFECTIVITY


Page 42Oct 95ALL


DescriptionWhen servicing the oil system by the remote fill methoduse a clear plastic hose attached to the overflowcoupling. This will give you a visual indication that thetank is full. Once oil is visible out the overflow hose stopservicing. Wait until the oil stops flowing from theoverflow drain line before disconnecting. If the overflowdrain line is removed before flow stops over servicing ofthe oil tank can occur. Always check couplings aftercompletion of servicing to insure that no leakage ispresent. A lightly wet surface, not sufficient to make onedrop, is permitted.

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EFFECTIVITY


Page 43Oct 95ALL

OIL TANK SERVICING (REMOTE FILL METHOD)

12-13-11

REMOTE OIL FILLOVERFLOW COUPLING

REMOTE OILFILL COUPLING


EFFECTIVITY



CHANGING ENGINE OIL

Description (2.D.b)When the changing of oil is required both gravity andpressure methods can be used. Also a drain adapter856A2506 may be required to drain the oil tank. Afterthe oil is drained service the system with new oil.

If a change from one brand of approved oil to anotherbrand of approved oil is required, draining is notnecessary and this may be accomplished through normalservicing. However, do not mix brands of oil on a regularbasis as this can lead to contamination due to chemicalincapabilities between oils.


EFFECTIVITY


Page 45Oct 95ALL

CHANGING OIL - DRAIN PLUG AND ADAPTER

12-13-11

DRAIN ADAPTER

OIL TANK

O-RING

MAGNETIC DRAIN PLUG

LOCKING PIN


EFFECTIVITY


Page 46Oct 95ALL

CHANGING ENGINE OIL

DescriptionAfter changing the oil, drain the accessory gearbox.Then operate the engine and do a check for leaks inaccordance with Test #3 Leak Check - Idle Power asindicated in the maintenance manual.


EFFECTIVITY


Page 47Oct 95ALL

CHANGING OIL - AGB DRAIN

ACCESSORY GEARBOXDRAIN PLUG

ACCESSORY GEARBOX

SCAVENGE OIL FILTER


EFFECTIVITY



FLUSHING THE OIL SYSTEM

Description (2.D.b)If contamination is suspected of entering the oil systemthen a system flush can be performed.

When flushing the oil system keep the old O-rings, theycan be used while flushing the system. In addition halfthe oil tank capacity is a sufficient quantity of oil to flushthe system.

A summary of the procedure is given below.


EFFECTIVITY


Page 49Oct 95ALL

OIL SYSTEM FLUSH SUMMARY

STEP 1: CHANGE THE OIL.

STEP 2: RUN ENGINE AT IDLE FOR TEN MINUTES.

STEP 3: CHANGE THE OIL.

STEP 4: INSPECT THE MCD'S.

STEP 5: REPLACE THE SUPPLY AND SCAVENGE FILTERS.

STEP 6: RUN AT IDLE FOR TEN MINUTES.

STEP 7: SERVICE THE OIL SYSTEM.

STEP 8: INSPECT THE SUPPLY AND SCAVENGE FILTER ELEMENTS.

STEP 9: RUN ENGINE AT IDLE FOR TEN MINUTES.

STEP 10: CHECK OIL FOR FUEL.

STEP 11: REMOVE, CLEAN, AND INSPECT MCD'S.

STEP 12: CHECK SUPPLY AND SCAVENGE FILTER ELEMENTS.

STEP 13: SERVICE OIL SYSTEM.

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EFFECTIVITY


Page 50Oct 95ALL


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EFFECTIVITY



POWER PLANT ADJUSTMENT AND TESTObjectives:At the completion of this section a student should be able to:....state the purpose of the power plant adjustments and tests of the CFM56-3/3B/3C engine (3.B.x).....describe the power plant adjustments and tests of the CFM56-3/3B/3C engine (3.E.x).


EFFECTIVITY



POWER PLANT - ADJUSTMENT/TEST

Purpose (3.B.a)Provide information to conduct the necessary tests tomake sure that the engine operates correctly afterreplacement of a line component.

The tests go from those with no engine run to those witha MEC trim or a vibration survey check.

The tests have numbers for positive identification:

Test No. Title of the Test

1. Pneumatic Leak Test2. Engine Motoring3. Leak Check - Idle Power4. Idle Speed Check5. Power Assurance Check6. MEC Trim7. Vibration Survey8. Accel/Decel Check9. Replacement Engine Test (Pretested)

10. Replacement Engine Test (Untested)11. T

2/Compressor Inlet Temperature

(CIT) Sensor Test

The chart below shows the line replaceable componentsand the applicable test required after replacement.


EFFECTIVITY



POWER PLANT TEST REFERENCE TABLE (EXAMPLE)

COMPONENT REPAIRED OR REPLACED NECESSARY TEST

Basic Engine ComponentsFan Rotor BladesFuel Pump Drive SealN2 Rotor Rotation Drive Pad Seal

Engine Fuel System ComponentsFuel Pump Fuel Filter CartridgeServo Fuel HeaterFuel NozzleMain Engine Control (MEC)CIT SensorCBP Sensor/Filter

Ignition System ComponentsIgnition exciterIgnition LeadIgniter Plug

Bleed and Air Control Systems ComponentsVariable Stator Vane (VSV) ActuatorVSV Feedback CableBleed Valve Fuel Gear MotorVBV Feedback Cable

763

633633

System Test (74-00-00/501)System Test (74-00-00/501)System Test (74-00-00/501)

3, 8838


EFFECTIVITY



TEST NO. 1 - PNEUMATIC LEAK TEST

Purpose (3.B.a)Referencing 36-11-05/501, Engine Bleed Air DistributionSystem this procedure will have maintenance personnelexamining these pneumatic ducts for a leak:

- Starter duct (up to the start valve).

- 5th and 9th stage ducts (up to the bleed air checkvalve and the high stage valve).

- Anti-ice duct on the inlet cowl (up to the ThermalAnti-ice (TAI) valve).


EFFECTIVITY



ENGINE PNEUMATIC DUCTING

RIGHT SIDE

PRESSUREREGULATING ANDSHUTOFF VALVE

(PRSOV) STARTER AIR DUCT TAI DUCT

9TH-STAGEDUCT 5TH-STAGE

DUCT

HPT-LPT COOLINGAIR TUBE

LEFT SIDE

HPT-LPT COOLINGAIR TUBE

5TH-STAGEDUCTPRSOV TAI DUCT

HPT SHROUD MANIFOLDAIR TUBE

HPT-LPTCOOLING AIR

TUBE

HPTCLEARANCECONTROL

VALVE(HPTCCV)

9TH-STAGEDUCT

9TH-STAGE BLEEDAIR TUBE

HIGHSTAGE

BLEED AIRVALVE

HIGH PRESSURETURBINE (HPT)-LPTCOOLING AIR TUBE


EFFECTIVITY



TEST NO. 2 - ENGINE MOTORING

Purpose (3.B.a)The engine motoring procedure can be used for anyoperation requiring engine rotation by starter only.

Maintenance Tasks (3.E.a)Motoring can be performed in dry mode (no fuelintroduced into the combustor) or wet mode (fuelintroduced into the combustor) as desired.

Dry motoring will determine that the engine rotates freely,that instruments function properly, and that the startermeets requirements for a successful start. Dry motoringcan also be used to check the lube system aftermaintenance , cool the engine down for borescopeinspection, or to clear residual fuel that may haveaccumulated in the combustion chamber or low sectionof the turbine casing.

Wet motoring is only used to depreserve the fuel systemafter storage.

Following starter limitations as outlined in the Boeing 737maintenance manual do the dry or wet motor procedure,as it is necessary for the required test (reference 71-00-00/201).

Examine the applicable component or system when youmotor the engine.

- Make sure that the component or system operatescorrectly.

- Make sure that there is no leakage.


EFFECTIVITY



REASONS FOR DRY MOTORING

DETERMINE FREE ROTATION OFENGINE.

PROPER FUNCTION OFINSTRUMENTATION.

PROPER STARTER FUNCTION.

CHECK LUBE SYSTEM AFTERMAINTENANCE.

COOL ENGINE FOR BORESCOPEINSPECTION.

CLEAR RESIDUAL FUEL FORMCOMBUSTION CHAMBER.

REASONS FOR WET MOTORING

DEPRESERVATION OF THE FUELSYSTEM.

ENGINE MOTORING


EFFECTIVITY



TEST NO. 3 - LEAK CHECK - IDLE POWER

Purpose (3.B.a)The idle leak checks test for the following correct engineoperation:

- The connections do not have a leak.

- The operational noise is correct.

- All of the engine-related instruments have thecorrect indications.

Maintenance Tasks (3.E.a)Do a visual leak check, if you disconnected the enginetubes during the maintenance procedure (and you did notdo a static pressure check).

The following pages show the key areas to check.


EFFECTIVITY





EFFECTIVITY




Maintenance TasksCheck for evidence of fuel leakage from fuel manifoldand fuel drain manifold on engine core.

Check for evidence of internal fuel leaks, indicated asfuel dripping from fuel drain lines (refer to 71-71-00 I/Cfor allowable leakage and corrective action).


EFFECTIVITY



ENGINE FUEL SYSTEM LEAK CHECK

FUEL NOZZLE(20 PLACES)

FUEL SUPPLYSHROUD

DRAINMANIFOLD

MAIN OIL/FUELHEAT

EXCHANGERDRAIN

VBV FUELGEAR MOTORSEAL DRAIN

LEFT VSV ACTUATORSEAL AND SHROUD

DRAIN

FUEL SUPPLY ANDMANIFOLD

SHROUD DRAIN

A

NOTE: ENGINE BUILDUP EQUIPMENTNOT SHOWN FOR CLARITY

MEC CASINGDRAIN

MEC SHAFTDRAIN

FUELMANIFOLD

HPTCCV DRAIN AND RIGHTVSV ACTUATOR SEAL AND

SHROUD DRAIN

CIT SENSOR SHROUD DRAIN

FUEL PUMPPAD DRAIN

SEE

SEE A

B

FORWARD

FORWARD FUEL DRAIN LINES

B


EFFECTIVITY




Maintenance TasksExamine the following oil system plumbing for damageand/or leaks:

- Main oil/fuel heat exchanger (1).

- Servo fuel heater (2).

- "Oil in" tube (3) from scavenge oil filter (13) to servofuel heater (2).

- "Oil out" tube (4) from servo fuel heater (2) to oiltank (14).


EFFECTIVITY



ENGINE OIL SYSTEM PLUMBING AND LEAK CHECK

A

B

C

SEE

SEE

SEE

A

3

4

2

1


EFFECTIVITY




Maintenance TasksExamine the following oil system plumbing for damageand/or leaks:

- Scavenge oil filter (13).

- Oil supply filter (9).

- Magnetic chip detectors (8).

- Lubrication unit (7).

- Forward sump oil supply tube (5) from lubricationunit (7) to forward sump and TGB.

- Aft sump oil supply tube (6) from lubrication unit (7)to aft sump via 6 o'clock strut.

- AGB oil supply tube (11) from lubrication unit (7) toAGB.

- Scavenge oil filter inlet tube (10) from lubricationunit (7) to scavenge oil filter (13).

- TGB scavenge tube (12) from TGB to AGB.

- Oil tank (14).

- Oil tank magnetic drain plug (15).

- Aft sump scavenge tube (19) from aft sump tolubrication unit (7) via 6 o'clock strut.

- Forward sump scavenge tube (18) from forwardsump to lubrication unit (7).

- AGB scavenge tube (17) from AGB to lubricationunit (7).

- Lube supply tube (16) from oil tank (14) tolubrication unit (7).


EFFECTIVITY



ENGINE OIL SYSTEM PLUMBING AND LEAK CHECK

13

4

3

12

11

10 98

B7

6

5

4

19 18

817

16

15

14

C


EFFECTIVITY




Maintenance TasksCheck CIT sensor shroud drain tube for evidence of fuelleakage. If found, replace CIT sensor (73-21-02).


EFFECTIVITY



CIT SENSOR TUBING CHECK

SEE A

SEE B

FWD

CIT SENSORSHROUD DRAIN

A


EFFECTIVITY




Maintenance TasksVisually examine accessible CIT sensor tubing on fancase and engine core for the following:

- Evidence of fuel leaks.

- Cracks.

- Dents.

- Collapsed sections.

- Wear through.

- Kinks.

- Loose Fittings.


EFFECTIVITY



CIT SENSOR TUBING CHECK

CIT SENSORFUEL

TUBES

FWD

CIT SENSORFUEL TUBES

MEC

B


EFFECTIVITY




Maintenance TasksExamine T2.0 sensor element for damage or obstruction.

Examine the following:- Sensor housing for cracks, nicks, dents, and

scratches.

- Mounting flanges for cracks, bending, and distortion.

- Capillary tube for kinks or breakage.

- Fuel tubes for leaks.

Refer to 73-21-09 I/C for serviceable limits and correctiveaction.


EFFECTIVITY



T2 TEMPERATURE SENSOR CHECK

T2 TEMPERATURESENSOR ELEMENT

SEE A

SEE B

T2 TEMPERATURESENSOR ELEMENT

FAN CASE

CAPILLARYTUBE

INLET COWL

B

MOUNTINGFLANGES

SENSORHOUSING

FUEL TUBES

A

FORWARD


EFFECTIVITY



TEST NO. 4 - IDLE SPEED CHECK

Purpose (3.B.a)The idle speed check makes sure that the %N2 RPM iswithin the limits at both low and high idle.

Maintenance Tasks (3.E.a)If it is necessary, adjustments to the low or high idle aremade with the engine static on the MEC.

To get access to the adjustment for the high idle, youmust remove the adjustment for the low idle.


EFFECTIVITY


Page 23Oct 9571-00-00ALL

SPECIFIC GRAVITY, LOW IDLE AND HIGH IDLE, AND POWER TRIM ADJUSTMENTS

SEE A

SEE B

TAB SCREW

POWER TRIMADJUSTMENTSCREW FOR

O-RINGREPLACEMENT

LOW IDLE SPEED ADJUSTMENTFOR HIGH IDLE SPEED

ADJUSTMENT

SPECIFIC GRAVITYADJUSTMENT

FUELCONTROL

BOX

A


EFFECTIVITY




Maintenance TasksThe following is a summary of the low idle speed check.

- Record the ambient air temperature (outside airtemperature [OAT]) and barometric pressure.

- Start the engine (reference 71-00-00/201).

- Make sure that all of the bleed air and electricalloads are off.

- Let the engine operation become stable at the lowidle.

- Make sure that the %N2 RPM stays in the limits forthe OAT and barometric pressure.

Specific MEC part numbers require that no adjustmentsbe made to low idle at temperatures of 40°F (4°C) orbelow or 16°F (-9°C) or below. A low idle adjustmentbelow these temperatures can cause an incorrect lowidle speed schedule. The idle RPM is controlled by agovernor in the MEC that is not adjustable (not by theengine low idle speed schedule). Do a check of the lowidle speed, when it is possible, at a higher OAT thanthese temperatures (reference 71-00-00 adjust/test formore specific information).

If the %N2 RPM stays in the limits, continue to the highidle check.

If the %N2 RPM does not stay in the limits, adjust the lowidle.


EFFECTIVITY



LOW IDLE AND HIGH IDLE ADJUSTMENTS

PREFORMEDPACKING

MEC

WASHER(2 PLACES) SCREW

(2 PLACES)

HIGH IDLE SPEEDADJUSTMENT (INSIDE PORT)

B


EFFECTIVITY




Maintenance TasksThe following is a summary of the high idle speed check.

- With the engine at the low idle (no airbleeds orelectrical loads), open the IDLE CONT circuitbreaker (flight idle solenoid) on the circuit breakerpanel, P6.

- Make sure that the %N2 RPM increasesapproximately 10% and becomes stable at thetarget %N2 RPM.

- If the %N2 RPM is not in the limits, adjust the highidle.


EFFECTIVITY



LOW IDLE AND HIGH IDLE ADJUSTMENTS

PREFORMEDPACKING

MEC

WASHER(2 PLACES) SCREW

(2 PLACES)

HIGH IDLE SPEEDADJUSTMENT (INSIDE PORT)

B


EFFECTIVITY



TEST NO. 5 - POWER ASSURANCE CHECK

Purpose (3.B.a)The power assurance check is a good test for theperformance analysis of the engine. The check shouldnot be used by itself for the acceptance or rejection of anengine.

This procedure may be used as a functional test todetermine the general condition of an engine and as adiagnostic for troubleshooting. This test gives anindication of the engine ability to produce the necessaryT/O power within the EGT and N2 limits during a full ratedT/O on a hot day (corner point) environment.

Maintenance Tasks (3.E.a)When you do this test as specified after maintenance,you must include a T/O power check to make sure theengine and system are serviceable.

If you do Test No. 8 (Accel/Decel Check) after this test, itis not necessary to do the T/O power check.

The corrected fan speed used for the maximum thrustrating is indicated in the chart below.

See the MPA tables in the Boeing 737 maintenancemanual for the corrected fan speeds of 80% N1, 85% N1,90% N1. The 90% N1 table where N1 is above the cornerpoint (30°C OAT) has been reduced to hold constant

EGT and N1 below CFM56-3-B1 T/O power.

You can use one of the three MPA fan speeds, howeverdo not exceed the engine operational limits, make sure touse the correct thrust rating, and think of the operatingthrust and the environment for the MPA fan speed youuse.

Use the power assurance check examples given in themaintenance manual to assist in calculating the EGT andN2 margins.

There may be adjustments to the EGT and N2 marginsfor engines equipped with a HPTCC timer, as well asaltitude and thrust level.

The power assurance check includes a T/O powercheck.If you wish to do a T/O power check only, use themaintenance manual procedure for the T/O power check.

It is recommended that you do Test No. 6 (MEC Trim)before you do the MPA and/or T/O power check for thesereasons:

- The MEC has not been trimmed.

- Faulty engine trim is suspected.


EFFECTIVITY



MAXIMUM THRUST RATINGS

18,500 88.3

20,000 90.4

22,000 93.7

23,500 95.3

MAXIMUM THRUSTPOUNDS

SEA LEVEL MAXIMUM CORRECTED*FAN SPEED (%N1K)

* From Boeing data, T/O power level, aircraft auto, PMC ON, standard day


EFFECTIVITY




Maintenance TasksThe following is a summary of the steps required to do apower assurance test. Refer to the Boeing 737maintenance manual for more specific information.


- Find and make a record of these values for thecurrent OAT on the MPA table you use.- The %N1 target

- The maximum EGT

- The maximum N2

- Crosswinds may have an effect on the engineoperation and cause the data to be less accurate. Ifit is possible, park the airplane such that it is pointedinto the wind.

- On engines with the HPTCC timer, make sure youdeactivate the HPTCC timer (reference 75-24-02/201). If you do not do this procedure, you can getunsatisfactory HPT blade clearances.

You must do this procedure before each high powertest (N2 RPM more than 94%) or series of enginetests (including both idle and high power tests). The

timer sets itself at each engine shutdown if it wasactivated in the previous test.

- Start the engine an let it become stable for fiveminutes at low idle. (reference 71-00-00/201).

- Make sure that all the bleed air and electrical loadsare off.

- Make sure the engine indications are in the correctranges.

- Make sure the applicable PMC switch is in the ONposition, and the PMC INOP light is off.


EFFECTIVITY



Maximum EGT - °C Maximum %N2

%N1

OAT Target Thrust Rating - Pounds Engine Model

°F (°C) ±0.5% 18.5K 20K 22K 23.5K -3-B1 -3B-2 -3C-1

28 (-2) 87.5 812 788 748 745 95.9 95.3 94.630 (-1) 87.6 816 792 751 748 96.1 95.5 94.832 (0) 87.8 819 796 755 752 96.2 95.6 94.934 (1) 87.9 823 799 758 755 96.4 95.8 95.136 (2) 88.1 827 803 761 759 96.6 96.0 95.337 (3) 88.2 830 806 765 762 96.7 96.1 95.539 (4) 88.4 834 810 768 765 96.9 96.3 95.641 (5) 88.5 838 813 772 769 97.0 96.4 95.843 (6) 88.7 841 817 775 772 97.2 96.6 95.945 (7) 88.9 845 820 779 776 97.3 96.7 96.046 (8) 89.0 848 824 782 779 97.5 96.9 96.248 (9) 89.1 852 828 785 782 97.7 97.0 96.350 (10) 89.3 856 831 789 786 97.8 97.2 96.552 (11) 89.5 859 835 792 789 98.0 97.4 96.754 (12) 89.6 863 838 796 793 98.1 97.5 96.855 (13) 89.7 867 842 799 796 98.3 97.7 97.057 (14) 89.9 870 845 802 799 98.4 97.8 97.159 (15) 90.0 874 849 806 803 98.6 98.0 97.361 (16) 90.1 877 852 809 806 98.7 98.1 97.463 (17) 90.3 881 856 813 810 98.9 98.3 97.664 (18) 90.4 885 859 816 813 99.0 98.4 97.766 (19) 90.6 888 863 819 816 99.2 98.6 97.968 (20) 90.7 892 867 823 820 99.3 98.7 98.070 (21) 90.9 896 870 826 823 99.5 98.9 98.272 (22) 91.0 899 874 830 827 99.7 99.0 98.373 (23) 91.2 903 877 833 830 99.8 99.2 98.575 (24) 91.3 906 881 836 833 100.0 99.3 98.677 (25) 91.5 910 884 840 837 100.1 99.5 98.879 (26) 91.6 914 888 843 840 100.3 99.6 98.981 (27) 91.7 917 891 847 844 100.4 99.8 99.182 (28) 91.9 921 895 850 847 100.6 99.9 99.284 (29) 92.0 924 898 853 850 100.7 100.1 99.486 (30) 92.2 928 902 857 854 100.9 100.2 99.588 (31) 92.1 928 902 857 854 100.9 100.2 99.590 (32) 91.9 928 902 857 854 100.9 100.2 99.591 (33) 91.8 928 902 857 854 100.9 100.2 99.593 (34) 91.7 928 902 857 854 100.9 100.2 99.695 (35) 91.5 928 902 857 854 100.9 100.2 99.6

TEST NO. 5 - POWER ASSURANCE CHECKMPA TEST TABLE - 90%N 1 CORRECTED FAN SPEED

[*] Above 86°F (30°C), N1 is decreased to keep EGT constant.


EFFECTIVITY




Maintenance Tasks- Move the forward thrust lever to the applicable

power position (N1 target) as found in themaintenance manual charts. The tolerance is +0.5%N1.

- Let the engine become stable without throttleadjustments for a minimum of four minutes.

- Make a record of the N1, N2 and EGT.

- Slowly move the forward thrust lever to the idleposition.

If the N1 record is different from the N

1 target by more

than +0.5 %N1 tolerance, the test point should be done

again.

Find if there is a positive or negative difference betweenthe N

1 target and N

1 record.

- If the N1 target is more than the N

1 record, there is a

positive (+) difference.

- If the N1 target is less than the N

1 record, there is a

negative (-) difference.

Adjust the EGT and N2 records using the difference

between the N1 target and the N1 record that you found.

For each 0.1 %N1 positive difference (N1 target morethan N1 record)

- Add 1.0°C to the EGT record to get EGTadjustment.

- Add 0.045% to the N2 record to get N2 adjustment.

For each 0.1 %N1 negative difference (N1 target less thanN1 record)

- Subtract 1.0°C from the EGT record to get EGTadjustment.

- Subtract 0.045% from the N2 record to get N2

adjustment.


EFFECTIVITY



DIFFERENCE

+.3

-.1

N1 TARGET

90.1

91.9

TEMPERATURE

61O F (16O C)

82O F (28O C)

N1 RECORDED

89.8

92.0

EGT CORRECTION

1.0O C * 3 = +3.0O C

1.0O C * 1 = -1.0O C

N2 CORRECTION

0.045% * 3 = +.135

0.045% * 1 = -.045

EGT AND N2 ADJUSTMENTS


EFFECTIVITY



- Correct the problems you find, and repeat the MPAtest.

If the initial MPA test was done under cold engineconditions, a second test would be a more satisfactoryindication of the engine condition.

Many conditions have an effect on the accuracy of theMPA test, thus the MPA test should not be used by itselffor the acceptance or rejection of an engine.

If the power assurance check is specified as necessaryfor after maintenance, do the T/O power check.

- If no more tests or corrections are necessary,shutdown the engine and return the aircraft tonormal configuration.


Maintenance TasksTo find the N2 and EGT margins do the following:

- N2 margin = N2 maximum - N2 adjustment

- EGT margin = EGT maximum - EGT adjustment

Adjust the EGT and N2 margins for these effects:- On engines equipped with a HPTCC Timer

operated at 22,000 pounds thrust or less, increasethe EGT margin by 17°C.

- On engines with ratings of 20,000 pounds thrust orless that operate at an altitude of 4000 feet orabove, decrease the EGT margin by 44°C.

- If an engine is operated with a rerated thrust use thetable to find the adjustment for N2.

If the EGT or N2 margins are more than the maximumlimits:

- shutdown the engine and troubleshoot for cause.

- Do a check of the N2 (ref. 77-12-00/501) and/or theEGT (ref. 77-21-00/501) indication system.

- Do a borescope inspection of the engine (reference71-00-00/601).


EFFECTIVITY



ADJUSTMENT FOR N 2

Thrust Rating CFM56-3-B1 CFM56-3-B2 CFM56-3C-1

20,000 +0.6% +0.6%18,500 +0.7% +1.3%


EFFECTIVITY




Maintenance TasksThe following is a summary of the steps required to doto do the T/O power check. Refer to the Boeing 737maintenance manual for more specific information.

- If not already done, record the ambient airtemperature (outside air temperature [OAT]) andbarometric pressure.


You must do this procedure before each high powertest (N2 RPM more than 94%) or series of enginetests (including both idle and high power tests). Thetimer sets itself at each engine shutdown if it wasactivated in the previous test.

- Start the engine an let it become stable for fiveminutes at low idle. (reference 71-00-00/201).



- Move the forward thrust lever to the static T/O N1.

- Make sure the engine accelerates smoothly.

- Let the engine become stable and make sure theengine instrumentation indications are in theoperation ranges.

- Move the forward thrust lever to the idle position.

- Make sure the engine decelerates smoothly and isstable at idle.

- If no more tests or corrections are necessary,shutdown the engine.


EFFECTIVITY





EFFECTIVITY



In the maintenance manual information for the specificgravity adjustment is in a different paragraph from thetrim adjustment. This will help in tests where only thespecific gravity adjustment is necessary.

Engine trim changes with the relative wind direction andvelocity. Therefore, do not adjust it when the winddirection and velocity are more than limits stated in theBoeing 737 maintenance manual (reference 71-00-00/201).

TEST NO. 6 - MEC TRIM

Purpose (3.B.a)This test gives the checks that you must do after a MECreplacement.

Maintenance Tasks (3.E.a)Do this test for the conditions that follow:

- If you think that you have incorrect engine trim

- The Power Plant Test Reference Table tells you todo this test after a component replacement.

This test gives the instructions for the specific gravityadjustment and the trim adjustment for part power.It also includes the following checks:

- The travel check and the static rig check for theVSV and VBV feedback cable.

- The gain check of the PLA transducer.

- The travel test for the engine control system.

- The idle leak check.

- The idle speed check.

- The power assurance check (optional).

- The accel/decel check.


EFFECTIVITY




A MEC TRIM CHECK INCLUDES THE FOLLOWING

TRAVEL CHECK FOR VSV AND VBV FEEDBACK SYSTEMS

STATIC RIG CHECK FOR VSV AND VBV SYSTEMS

PLA GAIN CHECK

TRAVEL TEST FOR ENGINE CONTROL SYSTEM

IDLE LEAK CHECK (TEST NO. 3)

IDLE SPEED CHECK (TEST NO. 4)

POWER ASSURANCE CHECK (TEST NO. 5) - OPTIONAL

ACCEL/DECEL CHECK (TEST NO. 8)

MEC TRIM CHECK


EFFECTIVITY




Maintenance TasksThe following is a summary of the steps required toprepare for the MEC trim. Refer to the Boeing 737maintenance manual for more specific information

- Make sure that the autothrottle PLA synchro iscorrect. Adjust it if it is necessary (reference 22-31-111/501).

- Make sure that the specific gravity position iscorrect.

Note: Use the specific gravity adjustment only to makethe correct adjustment for the type of fuel. Do not adjustit to change or correct the engine performance for adifferent problem. Incorrect adjustment can causeunsatisfactory engine performance.

If you change to a different fuel type, you must changethe specific gravity position on the MEC. On a flight legwith more than one type of fuel, no specific gravityadjustment of the MEC is necessary.

Make sure that the specific gravity position for the type offuel agrees with the table.


EFFECTIVITY



MEC SPECIFIC GRAVITY SETTING CHECK

MEC FUELCONTROL

BOXSEE A

MAIN ENGINE CONTROL (MEC) - BOTTOM VIEWA

FUEL SPECIFIC GRAVITY SETTING

JET A, JET A1, JP-1, JP-5, JP-8 0.82JET B, JP-4 0.77

CAUTION: SPECIFIC GRAVITY ADJUSTMENT IS ONLY TO ESTABLISH PROPER SETTING FORTYPE OF FUEL BEING USED. DO NOT ADJUST SPECIFIC GRAVITY AS AN ATTEMPTTO CHANGE OR CORRECT ENGINE PERFORMANCE FOR ANY OTHER REASON.

SPECIFICGRAVITY

ADJUSTER


EFFECTIVITY




Maintenance TasksViewing bottom of MEC, check setting of specific gravityadjuster, and compare to specification for fuel type.

- If required, adjust the specific gravity setting.



- Do the travel check for the VSV feedback cable andthe static rig check (reference 75-31-02/501).

- Do the travel check for the VBV feedback cable andthe static rig check (reference 75-32-05/501).

- Make sure that the specific gravity position iscorrect. Adjust it if it is necessary.

- Do the gain check of the PLA transducer (reference73-21-00/501).

- Do the travel test for the engine control system(reference 76-11-00/501).

- Do the idle leak check (reference Test No. 3).

- Do the idle speed check (reference Test No. 4).


EFFECTIVITY





EFFECTIVITY




Maintenance TasksThe following is a summary of the steps required to do aPart power trim check:

- Put the part power rig pin (C76001-2) through thepart power rig pin hole. The rig pin hole aligns withthe hole marked "P" at the fuel control box thisposition relates to 92.5° PLA. There are twopossible installation methods ( cowl closed or cowlopen).


- Start the engine and let it become stable for fiveminutes at low idle. (reference 71-00-00/201).




- Move the forward thrust lever against the part powerstop (92.5° PLA).

- Let the engine become stable for a minimum ofone minute.

- Make sure that the %N2 RPM is in the limits for thecurrent OAT and barometric pressure.


EFFECTIVITY



PART POWER RIG PIN INSTALLATION

1PART POWERRIG PIN HOLE

1

PART POWERRIG PIN

PART-POWER RIG PIN

LEFT FANCOWL PANEL

A

SEE B

REMO

VE BEFORE FLIG

HT

RED WARNING STRIPE (REF)

CSD ACCESS DOOR (REF)

FUELCONTROL

BOX

PART POWER RIG PIN(EXAMPLE)

B

PARTPOWERRIG PINSEE B

MEC

WARNINGSTREAMERRIG PIN

PR

REMO

VE BEFORE FLIG

HT

SEE A

FAN COWL PANELS WITHOUTPART POWER RIG PIN HOLE

FAN COWL PANELS WITHPART POWER RIG PIN HOLE


EFFECTIVITY




Maintenance Tasks- Look at the PART POWER (P-P) PMC OFF (%N2)

trim data listed in the maintenance manual(reference 71-00-01/201).

Note: There are numerous trim table configurations. TheBoeing 737 maintenance manual may or may not containall of these configurations. To avoid looking up incorrectdata insure that the effectivity block of the trim tablematches the configuration of the engine you are testing.

- Make sure that the MEC power trim is+0.5/-0.5 %N2 of the %N2 trim target.

If it is necessary, do an engine shutdown and adjust theMEC power trim.

Note: Adjust the MEC power trim to +0/-0.5 %N2 of the%N2 trim target. One full turn is approximately equal to a1.2% change in the N2 RPM, clockwise to increase RPM,counterclockwise to decrease RPM.


EFFECTIVITY



OAT oF

( oC )POWER SETTING

BAROMETER (INCHES OF MERCURY)

31.0 30.5 30.0 29.5 29.0 28.5 28.0 27.5 27.0 26.5

60

(16)

62

(17)

64

(18)

LOW IDLE (%N2)

HIGH IDLE (%N2)

P-P PMC OFF (%N2)

P-P PMC ON (%N1)

STATIC T.O. PMC ON/OFF (%N1)

ACCEL CHECK TARGET (%N1)

LOW IDLE (%N2)

HIGH IDLE (%N2)

P-P PMC OFF (%N2)

P-P PMC ON (%N1)



LOW IDLE (%N2)

HIGH IDLE (%N2)

P-P PMC OFF (%N2)

P-P PMC ON (%N1)

60.8

69.9

88.9

71.9

90.5

88.6

60.8

69.9

89.1

72.1

90.9

89.1

60.8

69.9

89.3

72.4

91.3

89.5

60.9

70.0

89.5

72.7

91.7

90.0

61.0

70.2

89.7

73.0

92.1

90.4

61.1

70.3

89.9

73.2

92.4

90.8

61.2

70.5

90.1

73.5

92.8

91.2

61.3

70.6

90.3

73.8

93.3

91.6

61.4

70.7

90.4

74.1

93.7

92.1

61.5

70.8

90.6

74.3

94.3

92.6

60.9

70.0

89.1

72.0

90.6

88.8

60.9

70.0

89.3

72.3

91.1

89.3

60.9

70.0

89.5

72.6

91.5

89.7

61.0

70.1

89.7

72.8

91.9

90.1

61.1

70.3

89.9

73.1

92.3

90.6

61.2

70.5

90.1

73.4

92.6

91.0

61.3

70.6

90.3

73.7

93.0

91.4

61.4

70.8

90.4

73.9

93.4

91.8

61.5

70.9

90.6

74.2

93.9

92.2

61.6

71.0

90.8

74.5

94.5

92.8

61.0

70.2

89.2

72.2

61.0

70.2

89.5

72.4

61.0

70.2

89.7

72.7

61.1

70.3

89.9

73.0

61.2

70.4

90.1

73.3

61.3

70.6

90.3

73.5

61.4

70.8

90.5

73.8

61.6

70.9

90.6

74.1

61.7

71.0

90.9

74.3

61.8

71.1

90.9

74.6

PART POWER TRIM CHART - PMC OFF


EFFECTIVITY




Maintenance Tasks- With the engine stable at the %N2 RPM target, push

the PMC switch to the ON position. Make sure thatthe PMC INOP light goes out.

- Let the engine become stable for a minimum oftwo minutes.

- Make sure that the %N2 RPM is in the limits for thecurrent OAT and barometric pressure.

- Look at the PART POWER (P-P) PMC ON (%N1)trim data listed in the maintenance manual(reference 71-00-01/201).

Note: If the %N1 RPM is not in the limits, start thetroubleshooting (reference 71-00-42/101) for a possiblePMC malfunction.

- Do the power assurance check (reference Test No.5) (performance of this check is optional).

- Do the accel/decel check (reference Test No. 8).


EFFECTIVITY



PART POWER TRIM CHART - PMC ON

OAT oF

( oC )POWER SETTING


31.0 30.5 30.0 29.5 29.0 28.5 28.0 27.5 27.0 26.5

60

(16)

62

(17)

64

(18)

LOW IDLE (%N2)

HIGH IDLE (%N2)

P-P PMC OFF (%N2)

P-P PMC ON (%N1)



LOW IDLE (%N2)

HIGH IDLE (%N2)

P-P PMC OFF (%N2)

P-P PMC ON (%N1)



LOW IDLE (%N2)

HIGH IDLE (%N2)

P-P PMC OFF (%N2)

P-P PMC ON (%N1)

60.8

69.9

88.9

71.9

90.5

88.6

60.8

69.9

89.1

72.1

90.9

89.1

60.8

69.9

89.3

72.4

91.3

89.5

60.9

70.0

89.5

72.7

91.7

90.0

61.0

70.2

89.7

73.0

92.1

90.4

61.1

70.3

89.9

73.2

92.4

90.8

61.2

70.5

90.1

73.5

92.8

91.2

61.3

70.6

90.3

73.8

93.3

91.6

61.4

70.7

90.4

74.1

93.7

92.1

61.5

70.8

90.6

74.3

94.3

92.6

60.9

70.0

89.1

72.0

90.6

88.8

60.9

70.0

89.3

72.3

91.1

89.3

60.9

70.0

89.5

72.6

91.5

89.7

61.0

70.1

89.7

72.8

91.9

90.1

61.1

70.3

89.9

73.1

92.3

90.6

61.2

70.5

90.1

73.4

92.6

91.0

61.3

70.6

90.3

73.7

93.0

91.4

61.4

70.8

90.4

73.9

93.4

91.8

61.5

70.9

90.6

74.2

93.9

92.2

61.6

71.0

90.8

74.5

94.5

92.8

61.0

70.2

89.2

72.2

61.0

70.2

89.5

72.4

61.0

70.2

89.7

72.7

61.1

70.3

89.9

73.0

61.2

70.4

90.1

73.3

61.3

70.6

90.3

73.5

61.4

70.8

90.5

73.8

61.6

70.9

90.6

74.1

61.7

71.0

90.9

74.3

61.8

71.1

90.9

74.6


EFFECTIVITY



TEST NO. 7 - VIBRATION SURVEY

Purpose (3.B.a)This test gives the necessary data to make sure that theengine vibration stays within permitted levels.

Maintenance Tasks (3.E.a)This test is applied after a component replacement as itis specified in the Power Plant Test Reference Table.

Use the vibration survey with the troubleshooting.

If the vibration levels are above the permitted levels,install the test equipment to isolate the source of thevibration.

Note: If the test equipment is not available, maximumengine vibration levels can be determined byinterrogating the AVM history data.


EFFECTIVITY



ENGINE VIBRATION ISOLATION TEST EQUIPMENT

TESTEQUIPMENT

UNIT

SHELF 2

SEE A

ELECTRONICEQUIPMENT

RACK, E1

SHELF 1

DIGITALANALOGADAPTER

NO. 1(REF)

SEE C

DIGITALANALOGADAPTER

NO. 2(REF)

A

SEE B


EFFECTIVITY




Maintenance TasksThe following is a summary of the steps required to do avibration survey. Refer to the Boeing 737 maintenancemanual for more specific information.



Note: Operate the CFM56-3-B1 engines at CFM56-3B-2power positions in this procedure only. The continuousoperation of the CFM56-3-B1 engines at the CFM56-3B-2T/O power positions will cause engine performancedeterioration.


- Find and make a record of the T/O power positionfor the current OAT and barometric pressure.

- Using the appropriate table lookup the STATIC T/O

PMC ON/OFF trim data (reference 71-00-01/201).

- If it is available, install the test equipment for theengine vibration isolation.

- Start the engine an let it become stable for twominutes at low idle. (reference 71-00-00/201).



- Move the forward thrust lever (within 20 to 30seconds) to the 80 +2 %N1 RPM.

- Let the engine become stable for a minimum ofseven minutes (this allows thermal stabilization ofthe engine and ensures accurate vibrationreadings).

- Move the forward thrust lever (within 20 to 30seconds) to the idle position.

- Let the engine become stable at the low idle for aminimum of 30 seconds.


EFFECTIVITY



ENGINE VIBRATION ISOLATION TEST EQUIPMENT

NOTE: ON SOME AIRPLANES, YOU WILL FIND THEAVM SIGNAL CONDITIONER ON SHELF 3

AVM SIGNALCONDITIONER

TESTEQUIPMENT

UNIT

B

CSELECTOR

SWITCH

VIBRATION ISOLATION SWITCH

FAN

LOW PRESSURE COMMONHIGH PRESSURE

HPT


EFFECTIVITY




Maintenance Tasks- Slowly move the forward thrust lever (at a constant

rate, that takes approximately two minutes toaccelerate) from the stable idle to the static T/Opower position in your records.

Note: The rate of the acceleration/deceleration must besufficiently slow (approximately two minutes) for you tofind a vibration maximum.

- Monitoring the applicable engine VIBRATIONindicator make a record of the N1 and N2% RPM,where vibration maximums occur.

- Let the engine become stable at the static T/Opower position for 30 seconds.

- Slowly move the forward thrust lever (at a constantrate, that takes approximately two minutes todecelerate) from the stable static T/O powerposition to the low idle.

- Again monitoring the applicable engine VIBRATIONindicator make a record of the N1 and N2% RPM,where vibration peaks occur.

- Let the engine become stable at the low idle.

- Increase the engine speed to the % RPM where youfound the highest engine vibration.

- Let the engine become stable for two minutes ateach point (if more than one).

- Make a record of all of the high vibration points thatyou found during the engine acceleration.

On Aircraft systems using AVM S360N021-100/-201 amean vibration reading of less than 2.5 units isacceptable. For all other AVM systems a mean vibrationreading of less than 3.0 units is acceptable.


EFFECTIVITY



1

VIB

VIBRATION INDICATOR

4

3

20

5

1


EFFECTIVITY




Maintenance TasksTo determine the source of the vibration do the following:

- Turn the selector switch on the isolation testequipment to find the source of the vibrationindications above the limits.

- You can also examine the history data in the AVMsignal conditioner. You will find the AVM signalconditioner in the EE bay area (reference 77-31-00/201).

Do the test again for all of the high vibration points thatyou found (if there are more than one) during the engineacceleration.

Do a dynamic fan rotor trim balance (reference 72-31-00/501), if you find that one of the following conditions is thesource of the high vibration:

- The high vibration is in the N1 rotor only (FAN and/or LPT).

- The high vibration is in the N1 rotor (FAN and/orLPT) and the N2 rotor (HPC and HPT).

- If you find the high vibrations only in the N2 rotor(HPC and/or HPT) and they are more than 3.0 units,then replace the engine (reference 71-00-02/401).


- If you installed it, remove the test equipment for theengine vibration isolation.


EFFECTIVITY



VIBRATION ISOLATION SWITCH

COMMON

HIGH PRESSURECOMPRESSOR

LOW PRESSURECOMPRESSOR

FAN HPT

VIBRATION ISOLATION


EFFECTIVITY



TEST NO. 8 - ACCEL/DECEL CHECK

Purpose (3.B.a)This procedure makes sure of a smooth accel/deceloperation with no stalls or flameouts.

Maintenance Tasks (3.E.a)You will do the check first with the PMC on, and then withthe PMC off.

The following is a summary of the steps required to doan accel/decel check. Refer to the Boeing 737maintenance manual for more specific information.


You must do this procedure before each high powertest (N

2 RPM more than 94%) or series of engine

tests (including both idle and high power tests). Thetimer sets itself at each engine shutdown if it wasactivated in the previous test.


Using the current OAT, barometric pressure, and theappropriate trim table from the Boeing 737 maintenancemanual, find and make a record of the following:

- STATIC T/O PMC ON/OFF N1

- ACCEL CHECK TARGET N1


EFFECTIVITY



OAT oF

( oC )POWER SETTING


31.0 30.5 30.0 29.5 29.0 28.5 28.0 27.5 27.0 26.5

60

(16)

62

(17)

64

(18)

LOW IDLE (%N2)

HIGH IDLE (%N2)

P-P PMC OFF (%N2)

P-P PMC ON (%N1)



LOW IDLE (%N2)

HIGH IDLE (%N2)

P-P PMC OFF (%N2)

P-P PMC ON (%N1)



LOW IDLE (%N2)

HIGH IDLE (%N2)

P-P PMC OFF (%N2)

P-P PMC ON (%N1)

60.8

69.9

88.9

71.9

90.5

88.6

60.8

69.9

89.1

72.1

90.9

89.1

60.8

69.9

89.3

72.4

91.3

89.5

60.9

70.0

89.5

72.7

91.7

90.0

61.0

70.2

89.7

73.0

92.1

90.4

61.1

70.3

89.9

73.2

92.4

90.8

61.2

70.5

90.1

73.5

92.8

91.2

61.3

70.6

90.3

73.8

93.3

91.6

61.4

70.7

90.4

74.1

93.7

92.1

61.5

70.8

90.6

74.3

94.3

92.6

60.9

70.0

89.1

72.0

90.6

88.8

60.9

70.0

89.3

72.3

91.1

89.3

60.9

70.0

89.5

72.6

91.5

89.7

61.0

70.1

89.7

72.8

91.9

90.1

61.1

70.3

89.9

73.1

92.3

90.6

61.2

70.5

90.1

73.4

92.6

91.0

61.3

70.6

90.3

73.7

93.0

91.4

61.4

70.8

90.4

73.9

93.4

91.8

61.5

70.9

90.6

74.2

93.9

92.2

61.6

71.0

90.8

74.5

94.5

92.8

61.0

70.2

89.2

72.2

61.0

70.2

89.5

72.4

61.0

70.2

89.7

72.7

61.1

70.3

89.9

73.0

61.2

70.4

90.1

73.3

61.3

70.6

90.3

73.5

61.4

70.8

90.5

73.8

61.6

70.9

90.6

74.1

61.7

71.0

90.9

74.3

61.8

71.1

90.9

74.6

PART POWER TRIM CHART - STATIC T/O AND ACCEL CHECK TARGET (%N1)


EFFECTIVITY




Maintenance Tasks- Start the engine an let it become stable for two

minutes at low idle. (reference 71-00-00/201).


- Open the applicable IDLE CONT circuit breaker onthe P6 panel and check that N2% is within limits forhigh idle.



- Manually set the N1 reference/target bug on theapplicable N1 indicator to the accel check target N1.

- Move the forward thrust lever to the static T/O N1.

- Let the engine become stable for a minimum of15 seconds.


- Move the forward thrust lever to the idle position.

- Let the engine become stable for a minimum of15 seconds.

- Quickly move the forward thrust lever (in onesecond or less) from idle to the full throttle positionmeasuring and making a record of the time it takesthe engine RPM to accelerate to the accel checktarget N1.

- Quickly move the forward thrust lever (withinone to two seconds) to the idle position making surethat the engine decelerates smoothly and becomesstable at idle.

- No flameout or compressor surge (stall) shouldoccur.


EFFECTIVITY





EFFECTIVITY




Maintenance TasksMake sure that the acceleration time from your records isnot more than 7.4 seconds.

If the engine uses more than 7.4 seconds in theacceleration, do the steps that follow:

- Do the accel/decel check again.

- Make sure that you let the engine become stable atthe accel check start N1 before the fast acceleration.

- If the acceleration time is more than 7.4 seconds,start troubleshooting (reference 71-00-42/101).

If no troubleshooting is necessary repeat the accel/decelcheck with the applicable PMC switch (located on thepilots' aft overhead panel, P5) in the off position.



EFFECTIVITY



ACCEL/DECEL CHECK

HIGH IDLE N1%

0 1 2 3 4 5 6 7 8 9 10

TIME - SECONDS

7.4SECONDS

ACCEL CHECKTARGET N1%


EFFECTIVITY



TEST NO. 9/10 - REPLACEMENT ENGINE TESTS

Purpose and Interface (3.B.a)This test provides necessary data after a new installationof a replacement engine.

Maintenance Tasks (3.E.a)Test No. 9 Replacement Engine Test (Pretested) isperformed if the replacement engine has completed oneof the tests that follow:

- The test occurred in an approved test cell with thevibration isolators on the engine mount.

- The engine operated satisfactorily with the vibrationisolators on the engine mount before the installation.

If you do not have a replacement (pretested) engine, thenyou must do the procedures in Test No. 10 ReplacementEngine Test (Untested).


EFFECTIVITY



ENGINE REPLACEMENT


EFFECTIVITY



TEST NO. 11 - T2 /CIT SENSOR TEST

Purpose (3.B.a)This test provides data for troubleshooting of the T

2 or

T2.5

(CIT) sensors for incorrect operation.

Maintenance Tasks (3.E.a)For the test, you use the ambient air temperature,operate the engine at low idle and read the pressuredifferentials across the T

2 and CIT sensors.

The condition of the sensors is found when you comparethe measured pressure differentials to the usual pressuredifferentials for the air temperature.

The following is a summary of the steps required toperform a test of the T

2 or T

2.5 (CIT) sensors. Refer to

the Boeing 737 maintenance manual for more specificinformation.

- Install the FIT/CIT sensor tester 856A1357.

- Get and write down the ambient air temperature inthe shade of the airplane.

- Start and operate the engine at low idle (reference71-00-00/201).

- Read the gages on the sensor tester and make arecord.

- Stop the engine (reference 71-00-00/201).

- Using the T2 /T2.5 (CIT) sensor limit data from thechart find the correct sensor limits for the outside airtemperature. Compare the gage values with thecorrect limits and determine the condition of thesensors.

- If the T2.5 (CIT) sensor is out of the limits, replacethe T2.5 (CIT) sensor (reference 73-21-02/401).

- If the T2 sensor is out of the limits, replace the T2

sensor (reference 73-21-09/401).

- If the sensors are in the limits, continue with thisprocedure.

- Remove the FIT/CIT sensor tester 856A1357.

- Do Test No. 3 - idle leak check (ref. 71-00-00/501).


EFFECTIVITY



-40 (-40) 48-68 29-49 42 (06) 90-110 59-79-38 (-39) 50-70 30-50 44 (07) 91-111 60-80-36 (-38) 51-71 31-51 46 (08) 92-112 60-80-34 (-37) 52-72 32-52 48 (09) 93-113 61-81-32 (-36) 53-73 32-52 50 (10) 94-114 62-82-30 (-34) 54-74 33-53 52 (11) 95-115 62-82-28 (-33) 55-75 34-54 54 (12) 96-116 63-83-26 (-32) 56-76 34-54 56 (13) 97-117 64-84-24 (-31) 57-77 35-55 58 (14) 98-118 65-85-22 (-30) 58-78 35-55 60 (16) 99-119 65-85-20 (-29) 59-79 36-56 62 (17) 100-120 66-86-18 (-28) 60-80 37-57 64 (18) 101-121 67-87-16 (-27) 61-81 38-58 66 (19) 102-122 67-87-14 (-26) 62-82 39-59 68 (20) 102-123 68-88-12 (-24) 63-83 39-59 70 (21) 104-124 69-89-10 (-23) 64-84 40-60 72 (22) 105-125 70-90-08 (-22) 65-85 41-61 74 (23) 106-126 70-90-06 (-21) 66-86 41-61 76 (24) 107-127 71-91-04 (-20) 67-87 42-62 78 (26) 108-128 72-92-02 (-19) 68-88 43-63 80 (27) 109-129 73-93

0 (-18) 69-89 43-63 82 (28) 110-130 73-9302 (-17) 70-90 44-64 84 (29) 111-131 74-9404 (-16) 71-91 45-65 86 (30) 112-132 74-9406 (-14) 72-92 46-66 88 (31) 113-133 75-9508 (-13) 73-93 47-67 90 (32) 114-134 76-9610 (-12) 74-94 47-67 92 (33) 115-135 77-9712 (-11) 75-95 48-68 94 (34) 116-136 78-9814 (-10) 76-96 48-68 96 (36) 117-137 79-9916 (-09) 77-97 49-69 98 (37) 118-138 79-9918 (-08) 78-98 50-70 100 (38) 119-139 80-10020 (-07) 79-99 51-71 102 (39) 120-140 81-10122 (-06) 80-100 51-71 104 (40) 121-141 82-10224 (-04) 81-101 52-72 106 (41) 122-142 82-10226 (-03) 82-102 53-73 108 (42) 123-143 83-10328 (-02) 83-103 54-74 110 (43) 124-144 84-10430 (-01) 84-104 54-74 112 (44) 125-145 85-10532 (0) 85-105 55-75 114 (46) 126-146 85-10534 (01) 86-106 56-76 116 (47) 127-147 86-10636 (02) 87-107 57-77 118 (48) 128-148 87-10738 (03) 88-108 57-77 120 (49) 129-149 87-10740 (04) 89-109 58-78

TEST NO. 11 - T2/T2.5 (CIT) SENSOR TEST LIMITS

AMBIENT AIR T 2 CIT AMBIENT AIR T 2 CITTEMPERATURE P7-PB P6-PB TEMPERATURE P7-PB P6-PB

°F (°C) PSID PSID °F (°C) PSID PSID


EFFECTIVITY





EFFECTIVITY


Page 1Oct 95ALL

BASIC TROUBLESHOOTINGObjectives:At the completion of this section a student should be able to:....state the purpose of troubleshooting the CFM56-3/3B/3C engine (3.B.x)..... recall the basic systematic process used when troubleshooting a CFM563/3B/3C engine (3.F.x)..... recall analyzing hints used when troubleshooting a CFM563/3B/3C engine (3.F.x)..... identify selected operational problems associated with the CFM56-3/3B/3C engine (3.F.x).

71-00-40


EFFECTIVITY


Page 2Oct 95ALL

INTRODUCTION

Purpose (3.B.a)Troubleshooting is the systematic process of identifying afaulty element in an otherwise functional system anddetermining the actions necessary to restore the system toan operational condition.

Troubleshooting (3.F.a)Troubleshooting begins with recognition and documentationof the problem. Precise documentation is essential toisolation of the fault with a minimum expenditure of time andeffort.

The Boeing 737 maintenance manual provides informationfor troubleshooting procedures that are in the form of flowcharts. These flow charts contain troubleshooting steps andcorrective actions in a recommended sequence based onprobability of component failure and ease of performingchecks required.

In addition to following the maintenance manual chartstroubleshooting procedures should be based on thefollowing assumptions:

- Double failures do not exist.

- The faulty system was fully operational prior to thefault indication with all equipment properly installed.

- All relevant circuit breakers were checked.

- All applicable airplane/engine operating procedureswere accomplished.

- The airplane is on the ground, it has been shut downin accordance with normal operating procedures andall power is off.

- Fault was accurately described.

All warnings, cautions and operating limitations associatedwith power plant maintenance and operation must beobserved during troubleshooting.

Generally, electrical wiring is considered to be satisfactory.The location of the wiring, its environment, exposure topossible damage and experienced failure rate will befactors in determining the need for electrical circuit checks.

71-00-40


EFFECTIVITY



MAINTENANCE MANUAL FAULT CHART

41 REPAIR/REPLACE THE ENGINE(71-00-02/401 AS NECESSARY.

IF FOD IS FOUND, REFER TOBIRD STRIKE/FOD TROUBLESHOOTING (71-00-47/101

1 VISUALLY EXAMINE ENGINE INLETAND EXHAUST AREAS FOR OBVIOUSSIGNS OF DAMAGE.

IS FOD AND/OR METAL PARTICLESFOUND?

3 ON ALL EXCEPT DLHAIRPLANES,DISCONNECT PLUG D3010 FROM J4RECEPTACLE ON PMC.

IS THERE CONTINUITY BETWEENPLUG SOCKETS 7 AND 8?

ON DLH AIRPLANES,CONTINUE ON TO BLOCK 5.

43 REPLACE THE P5-68 ENGINEMODULE ON THE P5 AFT OVERHEADPANEL (73-21-12/401)

45 ADJUST THRUST CONTROLPUSH-PULL CABLE (76-11-00/501

5 EXAMINE THRUST LEVER TOFUEL CONTROL BOX ADJUSTMENT(76-11-00/501).

IS THRUST LEVER TRAVEL/ALIGNMENT OK?

SEE SHEET 2BLOCK (7)

YES

NO

YES

YES

THROTTLE STAGGER


EFFECTIVITY


Page 4Oct 95ALL

observation only (opening of fan cowls or fan duct cowland thrust reverser halves for access may be required).Engine checks are more complex and may require testequipment, engine operation, and/or removal ofcomponents to accomplish.

Troubleshooting tips may be included in the sectionintroduction to describe typical problems to the mechanicor technician, and to alert of specific pitfalls that may beencountered.

TROUBLESHOOTING FAULT CHARTS

Troubleshooting (3.F.a)In the Boeing 737 Maintenance manual, powerplanttroubleshooting is separated into several major sections(see chart below).

Each section contains a listing of trouble symptomsassociated with the section. Each listed symptomincludes a reference to the troubleshooting chart andblock within the chart to begin troubleshooting for theparticular problem.

Troubleshooting charts are provided for major symptomsand each chart is given a figure number. Componentlocation illustrations and schematic diagrams are alsoprovided where essential to support troubleshooting.

Prerequisites are provided to assure that the system is inthe required mode, including the power required andidentification of the circuit breakers which need to beclosed ("in"), to perform the procedure. Time consumingoperations such as engine operation are noted.

Visual check (71-00-58) and engine check (71-00-59)sections provide details for checks that appearrepeatedly within troubleshooting charts or that have adegree of complexity requiring a detailed procedure orspecific illustrations to accomplish. Visual checks arethose checks which may be accomplished by visual

71-00-40


EFFECTIVITY


Page 5Oct 95ALL

STARTING AND IDLE 71-00-41POWER AND ENGINE RESPONSE 71-00-42SURGE (STALL) 71-00-43OIL SYSTEM 71-00-44FUEL SYSTEM 71-00-46MISCELLANEOUS OBSERVED PROBLEMS (VIBRATION, FOD, ETC.) 71-00-47ENGINE CONTROLS 71-00-49T/R 71-00-50FUEL INDICATING 71-00-53ENGINE INDICATING 71-00-54OIL INDICATING 71-00-55VISUAL CHECKS 71-00-58ENGINE CHECKS 71-00-59

71-00-40

BOEING 737-300/400/500 MAINTENANCE MANUAL TROUBLESHOOTING SECTIONS


EFFECTIVITY


Page 6Oct 95ALL OEB 600

VSV position.

If the VSV's are too far closed, then N2% will tend to shiftupward. This is caused by the fact that the N2% mustincrease to produce the same N1%. Often this is firstdetected on a hot day/full power takeoff and N1% cannotbe obtained because either the N2% reaches its limit orthe throttle stop is encountered.

If the VSV's are too far open, then N2% will tend to shiftdownward. These type of shift could be attributed to aCIT sensor failure.

If a trending of the D N2% shows an erratic scatter thenthe possibility of a sticking feedback cable could exist.

Fuel flow (Wf) trending by itself is not a good parameterto use for troubleshooting, but may be helpful when usedin conjunction with EGT and N2%.

Verify the problem first and use the on-board computers,flight recorders, maintenance manuals, etc. to help trackdown the problem.

TROUBLESHOOTING HINTS

Troubleshooting (3.F.a)EGT is the primary indicator for monitoring enginehealth. A gradual deterioration of EGT is considerednormal and can be expected on all turbine engines.

An EGT shift of 10 to 15°C can be expected due tocompressor or turbine damage, after FOD or DODingestion, turbine stator leakage, shroud to turbine tipdamage, or blockage of the turbine cooling system.These problems should be reported to maintenance formonitoring or corrective action.

Large EGT shifts of 25 to 30°C or more are indicative ofgreater compressor or turbine damage. Some exampleswould be HPT damage caused by liberated pieces of thecombustion chamber or bearing failure, etc.

Instrumentation failures are always a possibility andother parameters should be checked prior to majordecision making. Generally, EGT shifts or trendsdownward are an indication of a faulty instrument orinstrumentation system.

A trending of N2% is a good indication of VSVpositioning. Since VSV's are initially set on the ground,and N2% gages are not error free and are sometimeshard to read, D N2% is not used for absolute reading of


EFFECTIVITY


Page 7Oct 95ALL OEB 600

EXAMPLE - CRUISE TREND DATA REPORT

*********************************************************************************************** Aircraft Data En gine Performance Trendin g ******** (ADEPT) ******** ******** Version 10.1 PC12/93 ******** Copyright 1993 by GE Aircraft En gines ******** All Ri ghts Reserved ***********************************************************************************************

REPORT ID: CRDATA GE ENGINE CONDITION MONITORING PROGRAMCRUISE PERFORMANCE DATA - MOST RECE

----------------------CUAIRCRAFT AIRCRAFT ENG SERIAL ENGINE INSTALL N1 THRUST

ID TYPE POS NUMBER TYPE DATE MOD RATINGFGLZB A340-200 1 740183 CFM56-5C2 920101 3 -999

2 740135 CFM56-5C2 920101 1 -9993 740136 CFM56-5C2 920101 3 -9994 740140 CFM56-5C2 920101 2 -999

---------------------------------------------------------------FLIGHT DATA---------------------------------------ENG A/C ISO

DATE/ BLD PK VLV OIL FUELGMT TAT ALT MACH 1234 123 LRC N1 PRES FLOW V

41692=1 -31.8 33000 .788 1111 0 79.42 46. 2826.1706=2 79.41 51. 2844.

=3 79.42 43. 2824.=4 79.42 44. 2879.

42092=1 -32.0 39020. .812 1111 0 87.77 -55. 3025 -141=2 87.77 -55. 3115

=3 87.77 -55. 3020 -=4 87.78 -55. 3097 -


EFFECTIVITY


Page 8Oct 95ALL

N1 MISMATCH DURING IDLE DESCENT

Troubleshooting (3.F.a)Not all conditions are faults. CFMI has received anumber of reports from CFM56-3 operators experiencingengine-to-engine N1 differences of up to 15% duringdescent with the throttles on the idle stop. The greatestdifference occurs at the top of descent at high altitudesand airspeeds. The amount of mismatch graduallybecomes less as altitude and airspeed decrease. The N1

mismatch usually disappears by the time the aircraftdescends to 10,000 feet.

This N1 mismatch during idle descent is caused by alower operating line on some engines; i. e. the engine ismore efficient, so less fuel flow (Wf) is required tomaintain minimum idle N1 and N2 speeds. On theseengines at high altitudes and airspeeds, the scheduleddeceleration fuel flow (Wf) is sufficient to maintain N1 andN2 speeds higher than minimum idle. As the airplanedescends and/or slows down, the engines require morefuel to operate (engines less efficient due to operatingline moving up), so N1 and N2 decelerate towards idle.

The condition does not exist on all engine and (MEC)combinations, but may occur on one or more engines ona given airplane. The engine steady state operating linevaries due to engine component efficiencies, and thedeceleration fuel flow (Wf) schedule varies somewhatbecause of dimensional tolerances within the MEC. A

combination of engine operating line on the low side of itstolerance band (more efficient engine) and a decelerationfuel flow (Wf) schedule on the high side of its toleranceband can result in the "high" idle condition at highaltitudes and airspeeds.

With an efficient HPC, the fuel control decelerationschedule may intersect the steady state operating line.At the intersection point, the decel schedule results in afuel flow which is exactly that required for the engine tooperate steady state at that rotor speed. In order todecelerate, the engine requires a further reduction in fuelflow, but this cannot be achieved because the fuel controlwill not schedule fuel flow below the decel limit. As theairplane descends and slows to a lower airspeed, thesteady state operating line moves up (i.e., the enginerequires higher fuel flow for a given steady state rotorspeed). The intersection of the decel schedule and theoperating line moves down to a lower rotor speed andeventually the engine spools down to idle. The engineparameter mismatch during idle descent is aconsequence of a high efficiency engine.

The mismatch in N1 during idle descent is a normalengine characteristic. The condition will graduallydiminish with normal engine deterioration over time.

OEB303


EFFECTIVITY


Page 9Oct 95ALL OEB303

N1 MISMATCH DURING DESCENT

ENGINE A

ENGINE B

DECELERATION

SCHEDULE

N2

FUEL FLOW

Ps3

STEADY STATE

OPERATING LINE


EFFECTIVITY


Page 10Oct 95ALL

AIRCRAFT RUMBLE DURING IDLE DESCENT

Troubleshooting (3.F.a)Descent idle rumble can be characterized as a suddenonset of a perceived vibration while descending with astabilized idle setting (no thrust lever movement)between 15,000 and 9,000 feet. The vibration has beenreported over a very narrow engine speed range(typically 68-74% N2 or 30-35% N1) and is mostpronounced in the cockpit floor but it has also beenheard by flight crews on occasion. The onset of thevibration is not reflected on the Aircraft VibrationMonitoring (AVM) indicator. In addition, the vibration isnot necessarily repeatable flight-to-flight nor is it alwaysreproducible on the ground.

Investigation into the cause of descent idle rumbleindicates the phenomenon is the result of a lowamplitude non-synchronous engine vibration whichoccurs at low high pressure rotor axial loads and istransmitted into the airframe. This condition occurs atdescent idle thrust settings and is a normal enginecharacteristic which has no impact on engine or airframestructural integrity.

Although this phenomenon has been observed since thebeginning of the 737-300 program, in the past, theengine RPM at which the rumble occurs were in a rangewhere the engine did not operate for extended periods oftime. Since the deletion of minimum idle in flight, the

aircraft descent profile is such that the conditionsassociated with descent idle rumble are present for agreater portion of the descent.

Operator experience and recent flight testing indicatesthe descent idle rumble can be reduced/eliminated by aslight increase in engine RPM.

OEB304


EFFECTIVITY


Page 11Oct 95ALL


OEB304


EFFECTIVITY


Page 12Oct 95ALL

HOT START

Troubleshooting (3.F.a)A hot start is indicated by an abnormally rapid EGT rateof rise after lightoff. The EGT will exceed limits if thestart is not discontinued in time. By monitoring fuel flow(Wf) and EGT, a hot start can be anticipated anddiscontinued before limits are exceeded.

The chart below shows the relationship between theamount of temperature during a hot start and the amountof time the overtemperature exists. This relationship willdetermine the type of inspection or corrective action thatmust occur following a hot start.

71-00-41


EFFECTIVITY


Page 13Oct 95ALL

EGT OVERTEMPERATURE CHART (STARTING)

DNORMAL START

800

790

780

770

760

750

740

730725720

B

A

C

0 10 20 30 40 50 60

TIME - SECONDS

EG

T (

°C)

71-00-41


EFFECTIVITY


Page 14Oct 95ALL

SLOW/HUNG START

Troubleshooting (3.F.a)A slow/hung start occurs when following lightoff theengine displays and abnormally slow acceleration andRPM stabilization below idle. A hung start may be theresult of fuel scheduling being too lean or too rich. Alean hung start is associated with low fuel flow (Wf) and aproportionally low EGT. A rich condition can berecognized by a high fuel flow (Wf), an EGT rise whichmay tend to develop into an overtemperature conditionand possibly a rotating compressor stall.

71-00-41


EFFECTIVITY



LEAN HUNG START

LEAN FUEL SCHEDULE

LOW EGT

RICH HUNG START

RICH FUEL SCHEDULE

HIGH EGT

POSSIBLE OVERTEMPERATURE

POSSSIBLE STALL

SLOW/HUNG START CONDITIONS


EFFECTIVITY


Page 16Oct 95ALL

SLOW/DIFFERENTIAL ENGINE ACCELERATIONFROM LOW IDLE

Troubleshooting (3.F.a)CFM56-3 series engines can exhibit differentialacceleration times from low idle, which can affect T/Ooperation.

Investigations reveal that for both production and in-service engines, variation in acceleration time from lowidle can be exhibited. Above 40% N1, the enginesaccelerate with little variation. Tests of field engineshave identified a phenomenon that can contribute to on-wing differential acceleration. The graph below depictsthe relationship between the engine operating line andthe MEC acceleration schedule. The operating linerepresents the fuel/air ratio required to maintain asteady-state speed, and is not scheduled. An engine'soperating line is affected by engine health, enginethermal conditions, VSV tracking, pneumatic bleed, etc.It therefore differs from one engine to the next, and for agiven engine can change as the engine accumulatestime. Slow accelerating engines exhibit an upwardmigration of the low speed steady-state operating linetoward the fixed acceleration schedule. This reduces theacceleration margin and causes these engines toaccelerate more slowly from low idle.

71-00-42


EFFECTIVITY


Page 17Oct 95ALL

ACCEL SCHEDULE

ACCELMARGIN

NEWENGINE

ACCEL MARGINDETERIORATED ENGINE

STEADY-STATE OPERATINGLINE DETERIORATED ENGINE

DECELSCHEDULE

STEADY-STATEOPERATING LINE

NEW ENGINE

FUEL FLOWPS3K

LOW IDLE -40% N1

ACCELERATION MARGIN REPRESENTATION

71-00-42


EFFECTIVITY


Page 18Oct 95ALL

Adjusting low idle to the upper tolerance improvesacceleration time as well. As with VSV dynamic rig, theimpact on acceleration times is more pronounced forengines with low speed operating line migration. CFMI andBoeing have modified the MM tolerance for low idle to +3.0/-1.0% N2 (from +1.0/-1.0% N2) and high idle to +3.0/-0.7%N2 (from +0.7/-0.7% N2) to allow more flexibility in reducingon-wing engine-to-engine acceleration variation. Thisadjustment has also been successfully implemented in thefleet, and is particularly appealing since the adjustment isrelatively simple and quick.

Specific gravity adjustments help to improve start andacceleration times. Engines that have the 5th stage startbleed valve system can adjust specific gravity from 0.82 to0.78 as required. However, specific gravity adjustmentshould be accomplished after all other troubleshooting andcorrective actions have been performed.

A fault isolation procedure addressing engine differentialacceleration was introduced into the Boeing MM (71-00-42)in July 1989. As part of this troubleshooting procedure,adjustments to the low and high idle speed and VSVdynamic rigging may be performed on one or both enginesto minimize differential acceleration.


TroubleshootingSeveral procedures have been implemented by CFMI andBoeing to minimize and control differential acceleration fromlow idle. One of the changes recommended is the T/Othrust lever set procedure. Previously, the procedure calledfor positioning the throttles to the vertical position (60-70%N1) and allowing the engines to stabilize prior to performingthe final thrust lever set to T/O power. While this procedurehelps reduce differential acceleration/thrust during T/O, athrust lever pause at a lower N1 minimizes the differentialacceleration/thrust during the initial thrust lever set (fromlow idle to the pause speed). The revised procedurerecommends pausing at 40% N1, and provides a means toeffectively control differential acceleration during the entireT/O thrust lever set. The graph below depicts thisimprovement.

Also, opening VSV's within limits can improve engineacceleration characteristics, particularly on engines whichexhibit low speed operating line migration. A procedure foron-wing VSV dynamic rigging was introduced in April 1989.Special tooling is required to perform this procedure, whichis available through CFMI (VSV Dynamic Rig Tool No.856A1214 and 856A2001). Several operators havesuccessfully used this procedure to improve accelerationtimes, in the start range as well as from low idle.

71-00-42


EFFECTIVITY


Page 19Oct 95ALL

TIME IN SECONDSOLD 70% N1 PROCEDURE

FASTERACCELERATING

ENGINE

THRUSTDIFFERENTIAL

SLOWERACCELERATING

ENGINE

SLOWERACCELERATING

ENGINE

FASTERACCELERATING

ENGINE

THRUSTDIFFERENTIAL

TIME IN SECONDSNEW 40% N1 PROCEDURE

100

80

60

40

20

100

80

60

40

20

N1N1

CORRECTED CORE SPEED (N2K25)

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EFFECTIVITY


Page 20Oct 95ALL


TroubleshootingCFMI has identified excessive wear of the HPT nozzleW-seal as a strong contributor to low speed operatingline migration. Internal parasitic leakages past this sealat low speeds causes the operating line to be higher.Increased seal loading at higher speeds reduces theparasitic leakages, therefore minimizing the impact onhigher speed operating line. S/B 72-555 was issuedOctober 10, 1990 to introduce a new T800 coated W-seal. The coating of the W-seal was developed toprovide increased resistance to wear and cracking.

Finally, the CFM56-3 Workscope Planning Guide wasupdated to provide refurbishment recommendations forengines removed for slow acceleration.

71-00-42


EFFECTIVITY



HIGH PRESSURE TURBINE EXTERNAL ("W") SEAL

WIDTH

COATINGAREA

COATINGAREA

HIGH PRESSURETURBINE NOZZLE

ASSEMBLY

EXTERNAL ("W") SEALSEE CONFIGURATIONS 1,2,&3

CONFIGURATION 2COATING

AREACOATING

AREA

WIDTH

CONFIGURATION 1

CONFIGURATION 3


EFFECTIVITY


Page 22Oct 95ALL


TroubleshootingA procedure has been developed to evaluate engineacceleration time during troubleshooting. It has beenintroduced into the Boeing MM (71-00-42). In general,the procedure is as follows:

- Stabilize the test engine at low idle for a minimum ofthree minutes.

- With no bleed or horsepower extraction, rapidlyadvance the thrust lever in one second or less fromthe idle stop to the vertical position.

- Record the time from the initial thrust levermovement to 40% N1.

- Return thrust lever to idle.

Note: Setting the thrust lever to the vertical position (60to 70% N1) provides a smooth acceleration through the40% N1 test target.

Using this procedure, which provides a standard methodof measuring engine acceleration time from low idle, twoguidelines for engine acceleration are available for use atoperator discretion. They are strictly guidelines to assistmaintenance personnel during troubleshooting, and arenot cause for engine removal.

The first guideline was introduced into the Boeing MMtroubleshooting tree for differential acceleration in July1990. The above procedure is carried out for bothengines on the squawked airplane, and the accelerationtimes from low idle to 40% N1 compared. CFMI andBoeing consider a difference of four seconds or less tobe an acceptable guideline for terminatingtroubleshooting activity.

Some operators have stated that an absolute timeguideline from low idle to 40% N1 might be useful to theiroperations. For that reason, an acceleration timeguideline is established for engines that are squawked asslow to accelerate from low idle. Based on engine testdata and field experience, an acceleration time of 13seconds is considered acceptable for terminatingtroubleshooting activity. Commercial Engine ServiceMemorandum 031 introduced the 13-second guideline.

It is important to emphasize that adherence to the T/Othrust lever set procedure, which includes a thrust leverpause at 40% N1, will control the effects of differentialacceleration. Operators are strongly encouraged tostress the benefits of this thrust lever pause to flightcrews.


EFFECTIVITY



GUIDELINES/LIMITS FOR ACCELERATION TIME IN SECONDS

GUIDELINES FOR TROUBLESHOOTING SLOW/DIFFERENTIAL ACCELERATION

DIFFERENTIAL BETWEEN ENGINES

FROM LOW IDLE TO 40 % N1

4.0 SECONDS

13.0 SECONDS


EFFECTIVITY


Page 24Oct 95ALL


TroubleshootingA revised ground acceleration check (Test No. 8 Accel/Decel Check, 71-00-00) was implemented in November1994 to correlate ground accel times to in-flightperformance requirements. This check maintains a limitof 7.4-seconds from high idle to 95% Fn. If this limitcannot be met, troubleshooting must be initiated.

71-00-42


EFFECTIVITY



GUIDELINES/LIMITS FOR ACCELERATION TIME IN SECONDS

LIMITS FOR TROUBLESHOOTING SLOW/DIFFERENTIAL ACCELERATION

*NOTE: THE 7.4 SECOND VALUE FOR HIGHIDLE TO 95% FN IS CONSIDERED A LIMITAND NOT A GUIDELINE

FROM HIGH IDLE TO 95% THRUST 7.4 SECONDS *


EFFECTIVITY


Page 26Oct 95ALL


TroubleshootingSince upward migration of the engine operating line atlow engine speeds has been identified as a strongcontributor to increased acceleration time from low idle,evaluating the operating line of a given engine at low idlecan provide a means of better understanding an engine'scondition. CFMI has prepared a procedure for evaluatingthe engine operating line at low idle. It can be readilyapplied in the test cell, where all necessary parameters(N2, fuel flow (Wf), CDP and T2.5) are accuratelyinstrumented. This procedure can be adapted for on-wing use, although the result will not be as accurate as inthe instrumented test cell. The engine-mounted fuelflowmeter is not highly accurate in the low flow ranges,but is considered adequate for general operating lineassessment. The operating line is measured in terms of(fuel flow (Wf)/CDP)k. A pressure gauge or transducercan be installed in the CDP line - a 50 Pounds PerSquare Inch Absolute (psia) gauge/transducer isrecommended for low idle assessment, but cannot beused for higher power operation. T2.5 can be estimatedfrom OAT and N1, as used in the VSV dynamic rigprocedure. For low idle assessment, T2.5 isapproximately 6°F (3.3°C) higher than ambienttemperature.

In general, the low idle operating line for productionengines is 18-20 units. As this level increases,approaching the acceleration schedule (nominally 25.5units), acceleration time is expected to increase. Basedon inbound engine tests, operating lines of 22.5 andhigher at low idle are more likely to be squawked foracceleration problems.

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Page 27Oct 95ALL


71-00-42


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Page 28Oct 95ALL


TroubleshootingSome contributors to upward operating line migrationare:

- Engine health

- VSV scheduling

- Pneumatic system leakages

A Borescope Inspection (BSI), and review of such toolsas cruise trending (on-wing), engine history, and engineage can be helpful in understanding whether basicengine health may be a factor. However, some enginesexhibit high operating lines at idle without high EGT's atT/O or cruise. Cruise trending is not an indicator ofengine health at low speed and should be used only as ageneral engine health indicator.

VSV tracking has a very significant impact on the low speedoperating line. With VSV's tracking toward the closed sideof the tolerance band, the operating line will be higher;likewise, with VSV's tracking toward the open side of thetolerance band, the operating line will be lower. Severalcases of high operating line due solely to VSV tracking atthe closed tolerance have been experienced. In thesecases, opening VSV's brought the operating line andacceleration time down. The VSV dynamic rig tooling

provides a means of accomplishing this on-wing.Inspections of the pneumatic system/tubing can determinewhether air leaks are a factor.

Knowing an engine's low idle operating line can be helpfulin understanding the condition of an engine and in generaltroubleshooting. For example:

If an engine written up for slow acceleration has a very highoperating line that is not the result of pneumatic systemleakages, it may be more helpful to perform a VSV dynamicrig than an MEC change. The VSV dynamic rig will lowerthe engine operating line. A replacement MEC may trackricher or leaner than the original MEC. It is therefore notpossible to predict whether an MEC change will result infaster or slower engine acceleration.

If an engine is squawked for slow acceleration from low idle,yet has an operating line below approximately 22.0 units, itis possible that acceleration fuel scheduling may be toolean. This can be due to misadjusted Specific Gravity (SG),loose/leaking CDP line, MEC lean shift, etc.

71-00-42


EFFECTIVITY


Page 29Oct 95ALL

RECOMMENDED MAINTENANCE PRACTICES

OPERATING LINE ASSESSMENT

ENGINE HEALTH BORESCOPE, CRUISE TREND AND ENGINE HISTORY

VSV SCHEDULING STATIC RIG CHECK AND PERFORMANCE TREND

PNEUMATIC SYSTEM LEAKAGE VISUAL INSPECTION OF PNEUMATIC SYSTEM

CONTRIBUTORS TOOPERATIING LINE MIGRATION

71-00-42


EFFECTIVITY


Page 30Oct 95ALL


TroubleshootingThe intent of this procedure provides a means ofassessing engine operating line at low idle.

To begin the procedure install a 50 psia pressure gauge/transducer in the CDP line (near MEC). A 50 psiatransducer or gauge is adequate for low idle operatingline assessment ONLY. For speeds above low idle, ahigher range gauge/transducer would be required. Theprocedure is as follows:

- Record OAT and Pamb.

- Start engine and stabilize at low idle with nohorsepower extraction and bleeds off for fiveminutes.

- After stabilization, record N1, N

2, EGT, fuel flow (W

f),

and CDP.

- Shut engine down and perform calculation for (Wf/

CDP)k.

71-00-42


EFFECTIVITY


Page 31Oct 95ALL

QQQQQ25 = T2.5(°F) + 459.67

518.67

QQQQQ25 = T2.5 (°C) + 273.15

288.15

WF/CDPk = FF (PPH) X (QQQQQ25)-54

CDP (psia)

OPERATING LINE CALCULATION

WHERE T2.5 = OAT + BOOSTER RISE (REFER TO CHARTS IN VSV DYNAMIC RIG PROCEDURE)

AT LOW, IDLE T 2.5 = OAT (°F) + 6°F = OAT (°C) + 3.3°C

71-00-42


EFFECTIVITY


Page 32Oct 95ALL


TroubleshootingCFM56-3 engine acceleration from low idle is expectedto vary from engine to engine. Upward migration of thesteady-state low speed operating line has been isolatedas a contributor to increasing the acceleration time forsome engines as time is accumulated.

CFMI recommends several programs which have beendeveloped to minimize and troubleshoot slow/differentialacceleration. (see chart below)

A procedure for measuring and evaluating the low idleoperating line is included to assist in understandingengine characteristics and refine troubleshootingtechniques.

At shop level, the following are introduced:- Coated HPT nozzle W-seal

- Workscope Planning Guide refurbishmentrecommendations for slow acceleration engines

71-00-42


EFFECTIVITY



REVISED T/O THROTTLE SET

VSV ON-WING DYNAMIC RIG

IDLE SPEED ADJUSTMENT

SPECIFIC GRAVITY ADJUSTMENT

DIFFERENTIAL ACCELERATION TROUBLESHOOTING TREE

ACCELERATION LIMIT AND GUIDELINES

CFMI RECOMMENDATIONS FOR SLOW/DIFFERENTIAL ACCELERATION


EFFECTIVITY


Page 34Oct 95ALL

STUDENT NOTES

71-00-42

FLAMEOUT

Troubleshooting (3.F.a)An engine flameout can be recognized by an immediatedecrease in EGT, N2, and fuel flow (Wf), followed closely bya decrease in N1.

Investigate the cause of the flameout. If engine indicationsprior to the flameout, and investigation following theflameout do not reveal an engine malfunction or failure, arestart may be made.


EFFECTIVITY



FLAMEOUT RECOGNITION

012

10

8

2

4

6

06

5

4

1

23

00.6

91.7

00.8

007

658

009

00.3

83.4

00.5

93.4

CRZ

MAN SET

N1

EGT

N2

x 1000

PUSH

PULL

TO

SET

N1

PULL

TO

SET

N1

RESETFUEL

USED

%RPM

° C

%RPM

FF/FUKPGH/KG

FUELUSED

012

10

8

2

4

6

06

5

4

1

2

3

00.4

91.5

00.6

005

656

007

00.3

83.4

00.5

0.06

5.07

0.08

0.09

5.00

0.01

93.4


EFFECTIVITY


Page 36Oct 95ALL

N1 BLOOM

Troubleshooting (3.F.a)N1 "bloom" past takeoff target N1 is characteristic of a PMCOFF takeoff throttleset. When the PMC is off, the engine iscontrolled by the MEC, which schedules an N2K speedcorresponding approximately to a known N1K at steadystate. A throttle set for takeoff, however, results in atransient (dynamic) response in N2 and N1. The MECaccelerates N2 according to the acceleration fuel scheduleuntil N2K reaches the desired scheduled value for takeoff -this N2K is then maintained by the MEC. The dynamicresponse in N1, due to the transient changes in clearancesand component efficiencies, is a "bloom" past steady-stateN1 value by as much as 4-6% N1, prior to stabilizing at thesteady-state value. This bloom is typically several minutesin duration.

Impacts of this condition include overboost of takeoff N1

(thrust), and increased EGT during the N1 bloom. Theincrease in EGT (10-12oC per 1% sustained bloom duringthe bloom only) results from efficiency and clearancetransients and does not represent a permanent loss of EGTmargin

Engine thrust deviations (from intent) and/or fluctuationscan be caused by one or more fault possibilities. The initialfactor in troubleshooting an N1 bloom report is to firstdetermine if the T/O was done with the PMC OFF. ThePMC is designed to prevent this N1 bloom. If the T/O

71-00-42

occurred with the PMC OFF, no further troubleshooting isnecessary. If it is determined that the PMC was on, thensome type of failure has caused a saturation of the PMC'strim limits. The T/O N1 schedule is then the direct resultantof the N2 (MEC) schedule.


EFFECTIVITY



N1 BLOOM - PROPERLY RIGGED SYSTEM

N1 (PMC OFF)

N1 (PMC ON)

N2 (PMC OFF)

N2 (PMC ON)

TIME

TAKEOFF

TARGET

N1

N1

N2

Note 1: Airplane static.Note 2: This plot represents general

characteristics only.Note 3: Time = 0 corresponds to PLA

move to PMC off takeoff N2.


EFFECTIVITY


Page 38Oct 95ALL

N1 BLOOM

Troubleshooting (3.F.a)Anything which causes the PMC OFF N1 to be high at agiven N2 can cause N1 bloom during takeoff. With the N1

high at the MEC maintained N2, the PMC will require agreater N2 down trim signal to the MEC, to the extent ofpossibly running out of downtrim authority/capability(saturation). The speeds in this situation may react similarlyto those shown below, with the possibility of an N1 bloom.

Variable geometry (VSVs & VBVs) operating off schedule,causes such an N1/N2 shift. In this particular scenario,either the VSVs are operating more open than designintent, and/or the VBVs are operating further closed thendesign intent. Anything which can impact the way thevariable geometry operates - hardware, rigging, CIT sensor,MEC - is inspected/checked in the troubleshooting tree.

71-00-42


EFFECTIVITY


Page 39Oct 95ALL

N1 BLOOM - VSV'S TRACKING OPEN/OUT OF LIMITS

TIME

TAKEOFF

TARGET

N1

N1

N2

N1 (VSV OPEN)

N1 (VSV NORMAL) N2 (VSV NORMAL)

N2 (VSV OPEN)

SATURATION

IN DOWN TRIM

N1 (VSV OPEN)

N1 (VSV NORMAL)

N2 (VSV NORMAL OR OPEN)

TIME

TAKEOFF

TARGET

N1

N1

N2

PMC OFF PMC ON





EFFECTIVITY


Page 40Oct 95ALL

N1 BLOOM

Troubleshooting (3.F.a)If the PMC is not operating, the resultant takeoff will behaveas the characteristic PMC OFF takeoff, with N1 bloom. Thetroubleshooting tree incorporates two inspections whichcould cause this scenario. First, the aircraft P5-68 cockpitpanel is checked for possible failure which causes the PMCto be commanded off without illuminating the cockpit PMCinop light. Secondly, the N2 alternator, which powers thePMC, is checked for swelling of the alternator statorgrommet, which can intermittently interrupt power to thePMC, again without PMC inop light illumination.

Note: Modifications to both the P5-68 panel and theControl Alternator are available.

71-00-42


EFFECTIVITY





EFFECTIVITY


Page 42Oct 95ALL

N1 BLOOM

Troubleshooting (3.F.a)An engine which is improperly trimmed during the partpower trim test can result in an N1 bloom. In particular, ifthe PMC off N2 is high out of limits, the engine systemmay saturate in downtrim and be unable to fully eliminatethe total N1 bloom. For this reason, a part power trim testis included in the troubleshooting tree.

The original trim authority incorporated into MECs andPMCs was +/- 3.25% N2. However, with thisconfiguration, it was possible in some circumstances fora properly functioning system to become fully saturatedin down trim during takeoff. Service bulletins 73-043(PMC) and 73-048 (MEC) were introduced to increasethe trim authority to +3.85%/-5.1% N2, providing ampledowntrim margin to cover worst case stackups. In orderto obtain the benefit of increased torque motor authority,both service bulletins must be incorporated.

The troubleshooting tree lists the MEC and PMC partnumbers which incorporate the increased trim authority.If an engine is configured with old authority limits and isexperiencing N1 bloom, adjusting the PMC OFF N2 duringa part power trim run to the low side of the toleranceband will maximize the system's capability to successfullytrim the N1 bloom. This procedure is listed in thetroubleshooting tree as well.

71-00-42


EFFECTIVITY



N1 BLOOM - PART POWER TRIM ADJUSTED HIGH/OUT OF LIMITS




TIME

TAKEOFF

TARGET

N1

N1

N2

N1 (POWER TRIM HIGH)

N1 (NORMAL)

N2 (NORMAL)


TIME

TAKEOFF

TARGET

N1

N1

N2


N1 (NORMAL)

N2 (NORMAL)

N2 (TRIM HIGH)

PMC OFF PMC ON


EFFECTIVITY



N1 BLOOM

Troubleshooting (3.F.a)The MECs internal Rotary Variable DifferentialTransducer (RVDT) provides the PMC with a PLA signalfor use in determining target N1K. If the RVDT fails to"open" the PMC will perceive a PLA of 70o, regardless ofactual throttle position. The level of PMC trim authorityis a function of PLA, and at 70o there is virtually no trimcapability. Therefore, throttle sets are effectively PMCOFF, and N1 bloom is likely to occur. While the PMCtester and maintenance manual procedures are providedfor checking the RVDT, intermittent failures can occurespecially when the RVDT is heated. An extra step hasbeen added to the troubleshooting tree to run the engineat low idle for 5 minutes, then perform a 130o PLA gaincheck. With the RVDT heated, this check may be ableto detect an intermittent RVDT open.


EFFECTIVITY





EFFECTIVITY



N1 BLOOM

Troubleshooting (3.F.a)Internal failures of the MEC or PMC (or relatedcomponent) may cause N

1 bloom. Hence the PMC is

checked, and the MEC replaced at the conclusion ofother troubleshooting.

All known causes/contributors to N1 bloom are addressed

in the troubleshooting fault tree. Since there are manypotential causes of N

1 bloom on takeoff, the

troubleshooting tree is extensive, yet considerednecessary to effectively isolate the cause of a particularevent. Thorough troubleshooting per the MaintenanceManual is expected to identify and correct the cause ofN

1 bloom events.


EFFECTIVITY


Page 47Oct 95ALL



EFFECTIVITY


Page 48Oct 95ALL

THROTTLE STAGGER

Troubleshooting (3.F.a)Throttle stagger during manual operation with the PMCON should not usually be more than one-half knob.During autothrottle operations, up to approximately oneknob can occur, specially during cruise, when the thrustlevers can operate in different directions.

Throttle stagger with PMC OFF or inoperative can bemore than one knob as the thrust is controlled to N2%,not N1%. Because of engine to engine speed (N1%) -speed (N2%) relationships, different PLA settings canoccur for a given indicated N1%.

If the unsatisfactory engine is not known then it isrecommended that troubleshooting on both engines beperformed.

71-00-42


EFFECTIVITY


Page 49Oct 95ALL

THROTTLE STAGGER

ONE-HALF TO ONE KNOBTHROTTLE STAGGER CAN BEEXPECTED DURING NORMAL

OPERATIONS

SEE A

A

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UNABLE TO REACH T/O POWER

Troubleshooting (3.F.a)An upward shift of N2 means the HPC is turning fasterthan normal to produce the same N1 thrust. The problemshows up on a hot day full power T/O when N1 cannot beobtained because the N2/EGT limit has been reached orthe throttle lever has reached the limit stop.

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ENGINE SURGE/STALL

Troubleshooting (3.F.a)Engine stalls are caused by an aerodynamic disruption ofthe normally smooth airflow through the compressorstages. A stall may be indicated by different abnormalengine noises, loud reports accompanied by flames fromthe engine inlet, fluctuating performance parameters, andsluggish or no throttle response.

Compressor stalls can result in fatigue fracturing ofcompressor blades and severe thermal deterioration ofhot section parts. This may result in engine performancedeterioration or engine failure following a severe stall, butmore commonly, the full effects of a stall are deferredand consequently more difficult to correlate directly with aspecific stall occurrence. The deferred effects arecumulative and repeated stalls will adversely affectengine durability, reliability, and operating cost.

The decision to continue operation of an engine that hasencountered a severe compressor stall (or stalls) must bemade under the consideration that possible additionalstall occurrences and increased engine damage mayoccur.

Never advance, or fail to retard, the thrust lever on anengine that is stalling. Engine destruction can result.

If the cause of the stall is known (tailwind, crosswind, orlow airplane speed during reverse thrust) troubleshootingis not necessary after proper inspection of the engine.

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Page 53Oct 95ALL

EFFECTIVE ANGLE OF ATTACK VARIATIONS OF AXIAL FLOW COMPRESSOR BLADE

LEGEND:

A - INLET AIR VELOCITYB - IGV DISCHARGES AIR VELOCITYC - AIR MOTION RELATIVE TO ROTOR BLADE AS A RESULT OF COMPRESSOR RPMD - RESULTANT AIRFLOW AND VELOCITY ENTERING ROTORa - EFFECTIVE ANGLE OF ATTACK

AA A

BD

C C

D B

C

DB

aa a

COMPATIBLE INLET AIRVELOCITY AND RPMPROVIDES REASONABLEEFFECTIVE ANGLE OFATTACK (a).

RPM INCREASE WITHOUT INLETAIR VELOCITY WILL INCREASEEFFECTIVE ANGLE OF ATTACK (a).BLADE STALL, GENERALLY SHORTOF DURATION, MAY OCCUR.

INLET-AIR VELOCITYDECREASE WITHOUT RPMCHANGE CAUSES EFFECTIVEANGLE OF ATTACK (a) TOINCREASE. EXCESSIVE AIRVELOCITY DECREASE MAYRESULT IN BLADE STALL.

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Page 54Oct 95ALL

ENGINE SURGE/STALL

TroubleshootingThere are three types of stalls:

- Fan

- Booster (low pressure compressor)

- Core (high pressure compressor)

Fan stalls usually occur during high thrust operation withexcessive crosswinds or tailwinds. This type of stall isaudible, but not evident on engine instrumentation. Thesound of a fan stall is similar to that of an acetyleneblowtorch. A quick reduction in thrust is the best way toclear this type of stall.

Booster stalls occur during decels at high altitude andlow Mach number. Just like the Fan stall it is audible butnot evident to the engine instruments. This type of stallis generally self-recovering but may lead to a Core stall.

Core stalls can be experienced over the entire flightenvelope during both steady state and transientoperation. This type of stall may or may not be audible,but will have an effect on EGT, N2 and N1instrumentation.

If a core stall (surge) occurs do the following:- Quickly (in one to two seconds) move the throttle

71-00-43

lever rearward to idle power to clear the stall.

- Make sure that EGT and N2% decreases to normalidle indications.

- Make sure the engine vibration levels are normal.

You must shut down the engine for these conditions:- There is a high EGT, or

- A quick EGT increase occurs during slow throttlemovement, or

- An increase over previous vibration levels occurs.

Slowly move the throttle lever forward to see if the stallrecurs. If the stall does not recur and N2 and EGTindications are normal, continue with engine operation.

If the core stall occurs again, or if the stall does not clearsatisfactorily, operate the engine at low idle for threeminutes and shut down the engine to investigate.


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Page 56Oct 95ALL

ENGINE SURGE/STALL

TroubleshootingThere are two categories for engine stalls:

- High Thrust /Transient Stalls

- Off Idle and Start Stalls

High thrust/transient engine stalls are indicative of somesort of engine malfunction or exceedance of theoperating envelope.

This disruption of the airflow to the fan, booster, or coreairflow is generally due to FOD, VSV off schedule,excessive engine deterioration or Inlet distortion.

These types of stalls are very noticeable due to:- Abnormal engine noise

- Exhaust or inlet flame

- Fluctuating N1, N2, EGT, and fuel flow

- Excessive vibration

- Abnormal throttle response

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ENGINE SURGE/STALL

TroubleshootingOff Idle and start stalls are indicative of an enginemalfunction, misscheduling or an aircraft systemmalfunction.

Causes can be attributed to the disruption of compressorairflow due to inflow bleed, eccentric rotor clearances,excessive deterioration, VSV off schedule or excessivefuel schedule.

The detection is more difficult due to the lack noise orflame. However an abnormal increase in EGT and astagnation or rollback of rotor speeds will accompanythis type of stall.

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Page 59Oct 95ALL

STALLED START

STALLED START

STALLED START

NORMAL VERSUS STALLED START CHARACTERISTICS

TIME - SECONDS

0 5 10 15 20 25 300 5 10 15 20 25 30

70

60

50

40

30

20

10

TIME - SECONDS TIME - SECONDS

1,200

1,000

800

600

400

200

0

NORMAL START

FUELCHOPPED

FUEL CHOPPEDNORMAL START

NORMAL START

FUEL CHOPPED

0 5 10 15 20 25 30

800

700

600

500

400

300200

100

0

EGT(°C)

N2K(%)

FUELFLOW(PPH)

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71-00-00


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71-00-00

DIAGNOSTIC TOOLS FOR TROUBLESHOOTINGObjectives:At the completion of this section a student should be able to:....state the purpose of performing diagnostic engine runs of the CFM56-3/3B/3C engine (3.B.x).....describe the troubleshooting guidelines associated with a diagnostic engine run of the CFM56-3/3B/3C engine (3.D.x)..... identify the steps required to perform a diagnostic engine run of the CFM56-3/3B/3C engine (3.E.x)..... recall the normal and abnormal observations following a diagnostic run of the CFM56-3/3B/3C engine (3.F.x).....practice analyzing the diagnostic run data of a CFM56-3/3B/3C engine.....demonstrate analyzing the diagnostic run data of a CFM56-3/3B/3C engine.


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INTRODUCTION

Purpose (3.B.a)Because of the many engine sensors, componentriggings, etc. that affect CFM56-3 operationalcharacteristics, isolating the cause of a reported engineoperational problem can sometimes be difficult.However, troubleshooting the cause can be simplified byfirst accomplishing one or two engine ground runs, andanalyzing the collected data. The data can helpdetermine which system may be at fault, or whichsystems appear to be functioning correctly. With thisknowledge, the troubleshooting steps may be refined toinvestigate a more likely failure first, and eliminate (orpostpone) certain steps in troubleshooting trees, savingtime and unnecessary component replacements.

This section is intended to provide some basic guidelinesfor these engine run diagnostics. It is not intended toreplace the maintenance manual troubleshooting trees,but rather to enhance them.

It is also not intended, nor recommended, that each andevery pilot write-up be investigated with engine groundruns. The discretion of each airline should be used todetermine when such action is appropriate.


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GROUND RUNS

Description (3.D.a)Generally, three different engine ground runs are helpfulin assessing engine characteristics. Each should beperformed via proper maintenance manual procedures.It is recommended that data from both engines becollected for the runs, for two reasons: first, it allows abasis for comparing engines (N1K/N2K relationship, idlespeeds for differential accel adjustments, etc.); secondly,it is particularly helpful when troubleshooting a conditionwhere it is uncertain which engine may be at fault (i. e.throttle stagger). The three ground runs are:

- Low idle

- Part power trim check - rig pin installed, PMC ONand PMC OFF

- Max Power Assurance (MPA) check

For each of the checks, the following items should berecorded:

- Ambient temperature

- Ambient pressure

- Stabilization time

- N1

- N2

- EGT

- Fuel flow (Wf)

- PMC ON or off

- Targets from maintenance manual trim tables orMPA table

For the CFM56-3, there is a characteristic relationshipbetween steady-state N1K and N2K. It is very importantto understand that even on engines whose systems areoperating properly, there is some expected variation inthis N1K/N2K characteristic - for example, general enginedeterioration results in a shift in N1K/N2K (lower N2K for agiven N1K). Additionally, control system tolerances fromengine-to-engine can cause slight variations in N1K/N2Kbetween engines. For this reason, absolute N1K/N2Krelationship limits do not exist.


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GROUND RUNS

Description (3.D.a)However, if the variable geometry (VSV/VBV) is notscheduling correctly, an engine's N1K/N2K relationshipcan shift more dramatically, which can result in numerousoperational impacts, depending on the direction and levelof shift (throttle stagger, unable to reach T/O, N1 bloom,slow acceleration, stalls, etc.). As stated previously,there are no absolute limits of N1K/N2K; however, asignificant shift in the N1K/N2K relationship can bedetermined by comparing the two engines at matchedN1's or matched N2's. An assessment of the relative N1K/N2K relationship is most accurate at higher enginespeeds, such as MPA or T/O. Since a substantial shift inN1K/N2K is indicative of a problem somewhere in theengine's variable geometry system (VSV/VBV rigging/hardware, CIT, MEC), a higher power ground run canhelp determine whether the VSV/VBV system may be acontributor to an operational problem.


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GROUND RUNS

Description (3.D.a)The idle speed check is helpful in determining low speedengine health - particularly for squawks for slowacceleration or slow starts. A determination of availablelow idle speed adjustment (for slow/differentialacceleration from low idle) can also be made bycomparing the actual N2 with the maintenance manuallimits (higher N2 improves acceleration time from lowidle).

Because it is performed at a known throttle position, thepart power trim check is extremely helpful in determiningwhether the MEC (PMC OFF data) and PMC (PMC ONdata) systems are attaining the correct N2 (for the MEC)and N1 (for the PMC). The PMC and MEC use throttleposition, temperature and pressure to determine targetspeed. During a ground run, ambient temperature andpressure are known, so with the known throttle positionduring a part power trim run (92.5°), each system can beindependently checked. It is important that the rig pin beinstalled in the throttle box during this test - "ballpark"throttle positioning is not acceptable.

It is possible to compare the N1K/N2K of both enginesduring a part power trim check. However, it is importantthat the N1's be precisely matched, or the N2's beprecisely matched. If this is not possible at the partpower stop, perform the check during the MPA, where a

specific N1 is set on both engines.

The max power assurance check is helpful in tworespects - first, it provides a means of assessing anengine's general EGT health (for write-ups of high T/OEGT); secondly, it allows obtaining data on both enginesat a precise N1 target, so that a general comparison ofN1K/N2K can be made. If there is a significant differencein this relationship between the two engines, it isindicative of a VSV/VBV system (hardware, rigging,MEC, CIT) problem on one of the engines.


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GROUND RUNS

Description (3.D.a)The following pages provide the following:

- Procedures for performing each of the ground runs.

- Forms for collecting data from each of the groundruns.

- General observations about what may be learnedfrom the collected data.

Because of the difficulty inherent at times in isolating thecause of a particular pilot write-up, this section providesa means of more refined and efficient troubleshooting.Ground run data is very helpful because it is concreteand specific - pilot reports on engine anomalies are oftenvague, making efficient troubleshooting extremelydifficult.

The ground runs recommended in this document provideat least one of the following:

- Isolate which system may be at fault.

- Determine which systems appear to be functioningcorrectly, hence eliminating unnecessary engineinspections/component removals.

Again, these ground runs are not intended to replace themaintenance manual troubleshooting trees. The ground

runs allow an operator to use the troubleshooting treesmore effectively, postponing troubleshooting steps thatappear from the ground run data not to be contributing tothe reported problem, or pinpointing the faulty system totroubleshoot.


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etc.). Troubleshooting per the maintenance manual isstill recommended.

It is inaccurate to check N1K/N2K relationship at idlespeed - only at high engine speeds can this beaccomplished. The N1K/N2K relationship is insensitive toswings in VSV/VBV scheduling at low engine speed.

The PMC has no authority at idle, and thereforetroubleshooting for any problems identified at low idleshould not involve the PMC system, but be isolated tothe MEC system, engine hardware, or aircraft systems(per the MM troubleshooting trees).

IDLE SPEED CHECK

Maintenance Tasks (3.E.a)Perform idle speed check per the Boeing 737maintenance manual.

Stabilize at low idle for five minutes.

Record the following after five minutes' stabilization (seechart below).

Shut engine down per maintenance manual, or proceedwith other test point(s), if planned.

Observations (3.F.a)Engine N2 speed should be within maintenance manuallimits. Determine allowable adjustment available if the N

2

is out of limits, or if considering an adjustment for a slow/differential acceleration squawk.

Fuel flow (Wf) in the 800 Pounds Per Hour (PPH) range

or higher may be indicative (or support the possibility) oflow speed engine deterioration, particularly if the enginehas been written up for slow start/acceleration, hasrelatively high time, etc. (CESM 031 provides moredetails on low speed engine deterioration, and should bereferenced for more details). If the engine is new, orrecently overhauled, it is possible that another systemfault is causing the higher fuel flow (W

f) (pneumatic

leaks, VSV's tracking closed, idle speed out of limits low,


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Page 13Oct 95ALL

71-00-00

LOW IDLE SPEED CHECK RECORDING DATA SHEET

DATE:

TAIL NO:

AMBIENT TEMPERATURE:

AMBIENT PRESSURE:

STABILIZATION TIME:

ENGINE NO. 1 ENGINE NO. 2

N1:

N2:

EGT:

FUEL FLOW (W f):

N2 TARGET (FROM TRIM TABLE):


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PART POWER TRIM CHECK

Maintenance Tasks (3.E.a)Using the part power rig pin, perform part power trimcheck per the maintenance manual (PMC OFF and PMCON).

Stabilize for two minutes with PMC OFF, record databelow, then stabilize for two minutes with PMC ON, andrecord the data below.

Record the following after two minutes' stabilization (seenext page).

Per the maintenance manual, return the engine to idle.

Stabilize for five minutes, then shut engine down permaintenance manual, or proceed with other test point(s),if planned. Note that the rig pin will have to be removedif an MPA run follows this test point.

Use a duplicated chart for recording part power trim dataafter an adjustment is made (based on the results of theinitial run).


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Page 15Oct 95ALL

71-00-00

DATE: _______________

TAIL NO.: _______________

AMBIENT TEMPERATURE: _______________

AMBIENT PRESSURE: _______________

STABILIZATION TIME: _______________

PMC OFF PMC ON ENGINE NO. 1 ENGINE NO. 2 ENGINE NO. 1 ENGINE NO. 2

N1: _______________ _______________ N1: _______________ _______________

N2: _______________ _______________ N2: _______________ _______________

EGT: _______________ _______________ EGT: _______________ _______________

FUEL FLOW (W f) : _______________ _______________ FUEL FLOW (W f): _______________ _______________

N2 TARGET (FROM TRIM TABLE): _______________ N 1 TARGET (FROM TRIM TABLE): _______________

PART POWER TRIM CHECK RECORDING DATA SHEET


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PART POWER TRIM CHECK

Observations (3.F.a)The PMC OFF data offers information on how the MECsystem is scheduling N2 based on throttle position, ambienttemperature and pressure. The PMC OFF N2 value shouldbe within the limits specified in the maintenance manualtrim table. If it is not, adjust the part power trim screw perthe maintenance manual. If the target is still not met, moredetailed troubleshooting should follow: check Ps12 line(loose line causes low N2 speed), T2 sensor/lines (hot shift =high N2, cold shift = low N2), throttle rigging, etc.

PMC OFF N2 that is out of limits may cause PMC ON N1 tobe out of limits. Therefore, do not troubleshoot the PMCsystem because of not meeting PMC ON N1 limits until theMEC system (PMC OFF target N2) is operating correctly.

The VSV/VBV system scheduling will not affect whether thePMC OFF target N2 is met. Therefore, it is not necessary tocheck/inspect the VSV/VBV rigging or CIT sensor if thePMC OFF target is not met. These systems/componentswill, however, impact the resulting N1 speed at the target N2.

The PMC ON data offers information on how the PMCsystem is scheduling N1 based on throttle position, ambienttemperature and pressure. The PMC ON N1 value shouldbe within the limits specified in the maintenance manualtrim table. If it is not, first check the PMC OFF N2 - if it is outof limits, it can cause the PMC ON N1 to be out of limits -

correct the PMC OFF N2 problem first. If there is still aproblem with PMC ON N1, investigate the PMC system(PMC tester, T12, Ps12, PLA gain/voltage, etc.), and the VSV/VBV systems.


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PART POWER TRIM

ObservationsAs a general guide, a difference of up to approximately2% N1 between the two engines at perfectly matched N2'sis within normal revenue service experience. If thedifference is greater than 2%, it may be advisable tocheck the VSV/VBV rigging/hardware, and the CITsensor. Some possible engine behavioral characteristicswith VSV/VBV system scheduling improperly are asfollows (depends on severity of systemoff-schedule):

- VSV running closed or VBV running open:

- Slow starts/acceleration

-Throttle stagger, more pronounced PMC OFF (thisengine throttle leading)

- Unable to reach T/O target N1, with high N2

- Low/approach idle N2's OK

- VSV running open or VBV running closed:

- Compressor/booster stalls

- Throttle stagger, more pronounced PMCOFF (this engine throttle lagging)

- N1 bloom/high EGT on T/O


Note: Checking the relationship of steady-stateN1K/N2K can help isolate whether the VSV/VBV system/components may need to be inspected. Never adjustVSV's to attain a specific N1K/N2K - this can causeserious operational problems, including stalls, LPTovertemperatures, throttle stagger, inability to reach T/O, N1 overshoot/bloom, etc.


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MAX POWER ASSURANCE

Maintenance Tasks (3.E.a)Start engine per maintenance manual.

Perform MPA check per maintenance manualprocedures.

Stabilize for four minutes and record the data (see nextpage).

Per the maintenance manual, return the engine to idle.

Stabilize for five minutes, then shut engine down permaintenance manual.

Observations (3.F.a)Check EGT limit per the maintenance manual to attain ageneral assessment of engine health.

To make an assessment of N1K/N2K relationship at MPA:with the N1's perfectly matched between the No. 1 andNo. 2 engines (regardless of slight differences in throttleposition), it is expected that there will be some differencein the observed N2's. As a general guide, a difference ofless than 1% N2 between the two engines at perfectlymatched N1's is within normal revenue serviceexperience. If the difference is greater than 1%, it maybe advisable to check the VSV/VBV rigging/hardware,and the CIT sensor. With the N2's perfectly matched

between the No. 1 and No. 2 engines, it is expected thatthere will be some difference in the observed N1's. As ageneral guide, a difference of up to approximately 2% N1

between the two engines at perfectly matched N2's iswithin normal revenue service experience. If thedifference is greater than 2%, it may be advisable tocheck the VSV/VBV rigging/hardware, and the CITsensor.


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Page 21Oct 95ALL

71-00-00MPA

DATE:

TAIL NO:

AMBIENT TEMPERATURE:

AMBIENT PRESSURE:

STABILIZATION TIME:

ENGINE NO. 1 ENGINE NO. 2

N1:

N2:

EGT:

FUEL FLOW (W f):

PMC ON/OFF:

MPA TARGET:

MAXIMUM EGT (FROM TRIM TABLE):

MAXIMUM N2 (FROM TRIM TABLE):


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MAX POWER ASSURANCE

ObservationsSome possible engine behavioral characteristics withVSV/VBV system scheduling improperly are as follows(depends on severity of system off-schedule):

VSV running closed or VBV running open.- Slow starts/acceleration

- Throttle stagger, more pronounced PMC OFF (thisengine throttle leading)

- Unable to reach T/O target N1, with high N2


VSV running open or VBV running closed.- Compressor/booster stalls

- Throttle stagger, more pronounced PMCOFF (this engine throttle lagging)

- N1 bloom/high EGT on T/O


Checking the relationship of steady-state N1K/N2K can helpisolate whether the VSV/VBV system/components mayneed to be inspected. Never adjust VSV's to attain a

specific N1K/N2K - this can cause serious operationalproblems, including stalls, LPT overtemperatures, throttlestagger, inability to reach T/O, N1 overshoot/bloom, etc.


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POWER PLANT PRESERVATION AND DEPRESERVATIONObjectives:At the completion of this section a student should be able to:....state the purpose of preserving a CFM56-3/3B/3C engine (3.B.x).....state the purpose of an engine dry-out for a CFM56-3/3B/3C engine (3.B.x).....state the purpose of depreserving a CFM56-3/3B/3C engine (3.B.x).....describe the preservation guidelines of a CFM56-3/3B/3C engine (3.D.x).....describe the dry-out guidelines of a CFM56-3/3B/3C engine (3.D.x).....describe the depreservation guidelines of a CFM56-3/3B/3C engine (3.D.x).


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INTRODUCTION

OverviewThis section covers general information for power plantpreservation, preservation renewal and depreservation.

- The instructions usually apply to power plants thatare installed (on-wing).

- Where it is applicable, different instructions aregiven for engines that are not installed (off-wing).

The procedures are different for different lengths of nooperation time, different types of preservation used and ifthe power plant is serviceable or not serviceable.

Preservation renewal, if permitted, gives the instructionsfor the renewal of the preservation period.

Note: For this procedure, the definition of an engine thatis serviceable and an engine that is not serviceable is asfollows: a serviceable power plant is one that can bestarted; a power plant that is not serviceable is one thatcannot be started.


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PRESERVATION

Purpose (3.B.a)Preservation instructions give the proceduresrecommended as the minimum steps necessary toprevent unwanted liquid and materials in the power plant,corrosion, and atmospheric conditions during times ofstorage and no operation, or landing after an IFSD.

Description (3.D.a)Do the applicable preservation procedure from theschedule that follows:

- Up to 10 days

- Up to 30 days

- Up to 90 days (serviceable power plant only)

- 30 to 365 days

Power plant preservation is a flexible program that canbe done in a way which best agrees with the applicableweather and storage conditions.

More care is necessary for a program for power plantsthat are not operational in high humidity or largetemperature changes or near a salt water area, than forthe power plants that are in drier climates or less badweather conditions.

You must make a schedule for the preservation programs

for power plants that are not serviceable to do thepreservation renewal procedures and monitor the scheduleregularly to make sure the necessary procedures are donebefore the expiration of preservation time.

You must examine the preservation of the power plant asthe weather conditions and conditions of power plantprotection change and do the procedures necessary tokeep the power plant in a serviceable condition.

Note: Engines cannot be preserved and put into storagewithout maintenance. A schedule must be (as disciplinedas for a power plant in revenue service) made and thencompleted.

When desiccants are used, they must be changedregularly, applicable to environmental conditions, to keepthe desiccant effective.

It is recommended that you pump the VBV's closed(reference 75-32-00/201) when the power plant is to bepreserved and stored. This will prevent unwanted materialin the core engine inlet through the VBV's.

If a power plant is preserved for more than the long-termpreservation time (365 days), you must do the power plantoperation procedure to make sure the power plant isserviceable before you put the power plant back into serviceor preserve the engine for a longer time.


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PRESERVATION REQUIREMENTS CHART

UP TO 10 DAYS PRESERVATION



30 TO 365 DAYS PRESERVATION

3 MINUTE LOW IDLE RUNENGINE COVERSUNLIMITED RENEWAL

DRY-OUT PROCEDUREPERFORM WITHIN 24 HOURS OF IFSDNO RENEWAL

20 MINUTE LOW IDLE RUNENGINE COVERSRENEW 2 ADDITIONAL 30 DAYS

DRY-OUT PROCEDUREENGINE COVERSNO RENEWAL; PERFORM 30 TO 365 DAY

20 MINUTE RUN; PRESERVATIVE OILSENGINE COVERSNO RENEWAL; PERFORM 30 TO 365 DAY

NO RENEWAL; PERFORM 30 TO 365 DAY

TREAT OIL WITH ANTI-CORROSIVESTREAT FUEL SYSTEM WITH 10/10 OILDRY-OUT PROCEDUREENGINE COVERSDESSICANT WRAP ENGINE

EXTENSIVE PROCEDURE REQUIREDREFERENCE 71-00-03 FOR DETAILSNO RENEWALMAKE ENGINE OPERABLE

OPERABLE ENGINE NON-OPERABLE ENGINEPRESERVATION DAYS


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ENGINE DRY-OUT

Purpose (3.B.a)The engine dry-out procedure removes moisture fromthe oil system to prevent corrosion to the bearings andgears.

Description (3.D.a)You must do the engine dry-out procedure when an enginehas had an IFSD, and when an engine that is notserviceable will be preserved for a long time.

If an engine has been subjected to an IFSD and will not beoperated within 24 hours, a dry-out procedure must beperformed as soon as possible.


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NOTE: LAYOUT SHOWN FORENGINE OFF-WING;SIMILAR FOR ON-WINGINSTALLATIONS

DRY-OUT EQUIPMENT GENERAL LAYOUT

EXHAUSTPLUG

CLAMP

CLAMPS

HOT AIRSOURCE

HOSEAIRFILTER

HOSE


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DEPRESERVATION

Purpose (3.B.a)Depreservation instructions consist of steps that put apower plant back to the usual operational condition.

Description (3.D.a)The following is a summary of guidelines fordepreservation of a CFM56-3/3B/3C engine:

- Drain the oil and fuel systems of preservative fluids.

- Replenish the oil tank with new oil.

- Wet motor twice to purge fuel system ofpreservative fluids (dry motor after each wet motor).

- Replace oil and fuel filters.

- Perform engine test No. 3 (reference 71-00-00 A/T).Additionally, run engine for 10 minutes at low idleprior to shutdown.

- Check magnetic chip detectors.


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LUBRICATIONUNIT

SELFSEALINGSPOOL

GASKET

O-RING

PUSHER KEY(2 PLACES)

OILCONTAINER

AIR FLOW

OIL SUPPLYLINE

OIL SUPPLYLINE

OIL SUPPLYVALVE

AFT SUMPPUSHER

PLATE

SLEEVE

PLATE

KNURLEDBOLTS

(4 PLACES)

AIR SUPPLYLINE

ENGINE SUMPS RELUBRICATION MANIFOLD TOOL SET INSTALLATION

RELUBRICATION MANIFOLDUNINSTALLEDPUSHER C

AIR SUPPLYCONNECTOR

KNURLEDBOLT

A-A

AIRPRESSURE

SUPPLY LINE

O-RING

A

PUSHER

LUBRICATION UNIT

O-RING

FORWARDSUMP PUSHER

A

PUSHER KEYS(LOCKING PINS)

RELUBRICATIONMANIFOLD

GROOVE

KNURLEDPROTECTOR

TGB/AGBPUSHER

B

FORWARD

SEE C


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ENGINE GAS PATH CLEANINGObjectives:At the completion of this section a student should be able to:....state the purpose of gas path cleaning a CFM56-3/3B/3C engine (3.B.x).....describe the engine gas path cleaning process of a CFM56-3/3B/3C engine (3.E.x).


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INTRODUCTION

Purpose (3.B.a)Engine gas path cleaning restores engine efficiency bythe removal of particle contaminants from the primaryairflow path.

Experience has shown that an average 6°C EGT and0.5% specific fuel consumption can be realized. Thisaverage delta provides the most significant benefit tohigh time engines.


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AVERAGE DELTA EGT = 6°C

TIME SINCE INSTALLATION (TSI)

DE

LTA

° E

GT

C

CFM56-3 WATER WASH BENEFIT EXPERIENCE (TEST CELL)


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ENGINE WATER WASH

Maintenance Tasks (3.E.a)The following pages are a summarization of the CFM56-3 gas path cleaning procedure. To find more detailedinformation refer to the B737-300/400/500 MaintenanceManual.

Prepare the engine for the wash:- Disconnect the CDP and CBP lines at the

combustion case and put end caps on the lines.

- Make sure the left (right) start lever is in theCUTOFF position.

- Make sure the left (right) forward thrust lever is inthe IDLE position.

- Make sure the left (right) reverse thrust lever is inthe IDLE position.

- Make sure the left (right) ENG ANTI-ICE andBLEED switches are in the OFF position.

Detergent wash the engine:- Adhere to the following warnings and cautions:

- Use the rubber gloves when touching the solvent.Skin irritation can occur if you touch the solventbefore it is mixed.

- The cleaner is flammable. Obey the precautionsagainst fire. If you do not obey the precautions,injuries to persons can occur.

- Do not wash the engine if a fire extinguishingagent has been used. Damage to the engine canoccur.

- Do not wash the engine if the EGT indication ismore than 66°C. Engine damage can occur.

- Prepare the cleaning solution.

- Use the Power Plant Dry-motor procedure to motorthe engine for one minute (reference 71-00-00/201).

- Disengage the starter and immediately apply thecleaning solution through the fan blades and intothe LPC inlet.

- Apply the solution until the solution is gone or the N1

rotor stops.

- Let the engine soak for five minutes.

- Do the water wash procedure.

Make sure the N1 rotor turns freely when you wash theengine. If the N1 rotor does not turn freely, damage tothe engine could occur.


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Note: Obey the instructions in the procedure to open theT/R's. If you do not obey the instructions when you openthe T/R's, injuries to persons and damage to equipmentcan occur.

Open the left (right) T/R's. Let the engine drain for fiveminutes.

ENGINE WATER RINSE

Maintenance Tasks (3.E.a)Water rinse the engine:

- Adhere to the same cautions stated in the enginewash procedure.

- Use the Power Plant Dry-motor procedure to motorthe engine for one minute (reference 71-00-00/201).

- While the engine turns, apply water through the fanblades and into the LPC inlet.


- Motor the engine again for two minutes.

- While the engine turns, apply water through the fanblades and into the LPC inlet.


- Motor the engine again for three minutes.

- For the first two minutes only, apply water throughthe fan blades and into the LPC inlet.

- Open the fan cowl panels.


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ENGINE POST-RINSE

Maintenance Tasks (3.E.a)Prepare the engine:

- Connect the CDP and CBP lines.

- Add one quart (one liter) of Aeroshell fluid 12 oil, ifavailable, to the oil tank.

Operate the engine:- Operate the engine after no more than 30 minutes

from the last wash cycle to remove all the waterfrom the oil system.

- Operate the engine at low idle for five minutes.

- Make sure engine and APU bleed switches are inthe OFF position.

- Put the applicable ENG ANTI-ICE switch in the ONposition.

- Make sure there is an increase in the EGT ofapproximately 15°C

- Put the ENG ANTI-ICE switch in the OFF position.

- Move the forward thrust lever until the engine is inhigh idle. Put the applicable ENG ANTI-ICE switchin the ON position.

- Make sure there is an increase in the EGT ofapproximately 15°C.

- Put the ENG ANTI-ICE switch in the OFF position.

- Make the engine idle stable at the low idle positionand operate the engine for five minutes.

Shut down the engine.

Note: Make sure the COWL VALVE OPEN light comeson bright (this indication shows valve movement) andthen dim (this indication shows the valve fully open).

Note: Operate the engine for 10 minutes if the corrosioninhibiting oil was not added to the oil tank.


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Documents

71-00-00 Oct 95 - FlyingWay · cfm international CFM56-3 TRAINING MANUAL EFFECTIVITY CFMI PROPRIETARY INFORMATION Page 2 ALL 71-00-00 Oct 95 GROUND SAFETY PRECAUTIONS Overview (1.A.a)